The Nest: Most Influential Christian Theologians

As I was studying Hagiography last spring, I learned so much about the history of Christianity. Granted I already had a decent understanding of it, but definitely not the theological or ecclesiastic aspects. I was especially drawn to the 37 Doctors of the Church who shaped Catholic doctrine. So I first decided to study Augustine of Hippo with his most famous biographical work of Confessions. I then got a crash course on current Catholic Doctrine by reading the Catechism of the Holy Church. While this was refreshing to get up to speed on our current Catholic teachings, I still wanted to dive deeper. I wanted to trace the historical development of the world's largest religion. Not so much the spread of Christianity, rather the evolution of the theology.

I've mentioned before that the Catholic Church didn't just emerge out of the ground, yet rather needed centuries of theological discourse. It was thru theology, philosophy, and church councils that the church doctrine as we know it was developed. This for me has become one of the most fascinating topics I have ever studied. I suppose because it's a historical timeline of ideas and beliefs, rather than wars and empires. It wasn't a battle of armies, rather a battle of ideas. It so happens that these beliefs were at the center of all western history for the last 2000 years. Of course that has changed in the last couple hundred years, but Christianity still remains the largest religion in the world. This longevity is no doubt a credit to it's powerful theology, full of such wonder and mystery, that has continued to evolve since the teachings of Christ.

I've been deep into this theological study for a couple months now and just finished The First Thousand Years: A Global History of Christianity by Robert Louis Wilken. I've already written about the Ecumenical Councils, The Eastern Orthodox Churches, and the Eastern Catholic Churches. I even broadened my Christian theological study with a swim thru the basic concepts of all religion. Concepts such as the soul, the afterlife, and the question of a supreme being are shared by many religions. While I am always partial to Christianity, I am still very drawn to all religions and philosophy and one day may want to visit them from an academic stance. Nonetheless I stay with Christian theology for now, in what I believe should be my final few posts.

This one here is probably my most ambitious projects since my Top 100 Cathedrals list. With this post I am addressing the chronological development of Christian theology with it's key players. These are the most influential Christian theologians and philosophers who shaped Christianity as we know it. I'm also including the lead heretics, schismatics, and reformers who also played a significant role in the overarching discourse of Christianity. Each of these theologians present their own concepts and interpretations on the teachings of Christ, which became an influential movement (even if it was Orthodox or Heresy). I sometimes wonder if maybe the Orthodox Church was shaped by not so much the smartest minds, but rather the most convincing debaters. Nonetheless they often had a majority with them and the fact that these concepts have survived for so long make it all the more credible.

So this study of theology will trace the chronological development of the church doctrine after the resurrection of Christ. I'm going to begin with the main Apostolic theologians, and then break it down by centuries with the hot topic of the era. It's so interesting to see how these questions and concepts develop over time (especially in the first few hundred years). The questions of upholding Jewish customs, the date of Easter, the biblical Canon, defense against Roman paganism. Should Christian defectors during the persecution be readmitted? Is there secret knowledge in the bible? Is the bible allegorical or literal? Is Jesus God? Is the Holy Spirit God? Is God Trinitarian? Is Christ human or divine? What is his nature? What is his Will? Is Mary the Mother of God? Why does evil exist? Should religious icons be allowed? Is Jesus present in the Eucharist? Can Reason and Faith coexist? Can God be experienced thru Spiritual Mysticism? Should Scripture have more authority then the church? Should infants be baptized? Do we have free will or need salvation thru God's grace?

All of these questions will be explored here in this study of the Most Influential Christian Theologians.

Apostolic Theologians

St. Peter the Apostle

Theological Legacy: Foundation of Apostolic Christianity
Dates: 1-67
Location: Bethsaida, Galilee (modern day Israel)
Position: Apostle of Christ, Leader of Twelve Apostles
Influenced by: Jesus Christ, Jewish Scripture
Key Concepts:

Jesus as the Messiah and Son of God
The resurrection as the foundation of Christian hope
Christian suffering and perseverance
Holiness of life
The church as a royal priesthood and holy nation
Pastoral leadership and shepherding God's people
Hope amid exile and persecution

Major Works:

First Peter- Gospel book
Second Peter- Gospel book

Influenced: Clement of Rome, Ignatius of Antioch, Irenaeus, Early Church Fathers
Major Opponents: Simon Magnus
Titles/Honors: Saint, Cephas (Rock), Chief of the Apostles, First Pope, Keeper of the Keys
Canonized: Yes. Pre-congregation
Summary: He was Jesus' most loyal disciple and considered the chief of the twelve apostles. Christ personally asked him to become the rock that would build the church. After the ascension of Christ, Peter became one of the lead theologians, evangelizers, and administrators of the early church. He shaped some of the foundational church concepts centered on the life and resurrection of Jesus Christ. He emphasized the concepts of hope, holiness, suffering, and perseverance in faith thru God. He famously evangelized, preached, and even openly debated with other theologians such as Simon Magnus. Peter eventually established Rome as his headquarters of operations to become the first official pope (bishop of Rome). His martyrdom served as the ultimate example of his dedication and loyalty to the teachings of Christ. While it's no question that Paul and John were much more versed in theological development, the role of St. Peter as the founder of the church cannot be overlooked. His contributions in establishing the Christian church can ultimately be seen as the apostolic foundation of Christian theology.

St. Paul the Apostle

Theological Legacy: Architect of Christian Theology
Dates: 5-67
Location: Tarsus, Cilicia (modern day Turkey)
Position: Apostle to the Gentiles, Missionary, theologian
Influenced by: Jesus Christ, Jewish Scripture
Key Concepts:

Justification by faith
Salvation by grace
Union with Christ
The death and resurrection of Jesus as the center of salvation
The inclusion of Gentiles in God's new covenant
Life in the Holy Spirit
Christian freedom and sanctification

Major Works:

Romans
Corinthians 1 and 2
Galatians
Ephesians
Philippians
Colossians
Thessalonians 1 and 2
Timothy 1 and 2
Titus
Philemon

Influenced: Clement of Rome, Ignatius of Antioch, Irenaeus, Augustine of Hippo, Thomas Aquinas, Martin Luther, John Calvin, Karl Barth
Major Opponents: Judaizers (Christians who wanted to keep Jewish traditions), Pagans
Titles/Honors: Saint, Apostle to the Gentiles, Apostle of Grace, the Great Apostle
Canonized: Yes. Pre-congregation
Summary: He is considered the first proper Christian theologian, who could be considered the roots of all Christian theology. Quite interestingly Paul was not one of the original apostles but actually began as a Jewish Pharisee. Well-versed in Hebrew Scripture he was first very critical of the Christian movement, which even famously included the martyrdom of St. Stephen. However he later received a vision from Christ on the Road to Damascus which made him go blind for three days. During this period St. Paul came to understand the message of Jesus Christ and converted to become one of his most loyal disciples. Although Paul did not personally experience the life of Christ like the other apostles, he brought something quite unique then the others. He was an academic scholar who understood Jewish theology better then most, and used his knowledge as a foundation in developing the cornerstones of Christian theology. Some of his most influential concepts included emphasizing the fulfilment of the Old Testament as well as writing a majority of the new testament thru his missionary letters. Paul preached and wrote of the importance of grace, faith, salvation, and the Holy Spirit. He is also considered the champion of the Gentiles, who famously argued that the new Christian faith should allow Gentiles to practice without honoring Jewish customs (such as circumcision and other dietary rules). This could be seen as the beginning of separating Christianity as it's own religion and not just a sect of Judaism. This was the major topic at the first church council in Jerusalem (48 AD), which he oversaw. Paul did much of his missionary work traveling thru Syria, Asia Minor (modern day Turkey), and Greece. He later joined Peter in Rome, to help establish the foundation of Christianity, where he was also martyred. While Peter established the ecclesiastical blueprint, Paul established the theological blueprint of Christianity.

St. John the Apostle/Evangelist

Theological Legacy: Architect of the Logos
Dates: 6-100
Location: Galilee, Palestine; Ephesus (modern day Turkey)
Position: Apostle of Jesus Christ, Evangelist
Influenced by: Jesus Christ
Key Concepts:

The divinity of Christ
Love as the central Christian value
Eternal life through faith in Jesus
The Word made flesh (Logos)
Light vs Darkness (Good vs Evil)
Eternal Life
The Apocalypse and Judgement Day

Major Works:

Gospel of John
First Epistle of John
Second Epistle of John
Third Epistle of John
Book or Revelation

Influenced: Church fathers, Christian mysticism
Major Opponents: Jewish authorities, Roman-Pagan authorities
Titles/Honors: Saint, John the Apostle, John the Evangelist, The Belove Disciple
Canonized: Yes. Pre-congregation
Summary: He is arguably the third most important apostle after Paul and Peter in regards to the early development of the Christian church and theology. It is well documented in the gospels that he had a special relationship with Christ, often referred to as the "Beloved Disciple". This is clear in his Gospel, which is quite different than the other 3 Evangelists (known as the Synoptic Gospels). While Matthew, Mark, and Luke explain what Christ did, John's writing explains who Jesus is. It is thus filled with much more theological and spiritual detail, especially pertaining to the divinity of Jesus Christ. Thru his writing John could be considered the father of the Logos concept, as he famously declares "In the beginning was the Word. And the Word was with God, and the word was God". This statement essentially declares the Logos principle that Christ was there at the beginning and was the incarnate flesh of God. John also famously provided great mystical detail in his Book of Revelation which described the Apocalypse, Judgement Day, and the Second Coming of Christ. He can thus also be considered the first proper Christian mystic. John no doubt had the blessing of God, since he is the only apostle to have not died of martyrdom rather thru old age.

1st century (Post-Apostolic Church Fathers)

Clement of Rome

Theological Legacy: Advocate of Church Unity
Dates: 35-99
Location: Rome, Roman Empire
Position: Bishop of Rome
Influenced by: Apostolic Tradition, Peter and Paul, early disciples and companions of the apostles
Key Concepts:

Church authority and unity
Apostolic tradition and succession
Obedience and humility
Structure within the church

Major Works:

First Epistle to the Corinthians (1 Clement)

Influenced: Ignatius of Antioch, Irenaeus of Lyons
Titles/Honors: Saint, Apostolic Father, Pope
Canonized: Pre-congregation
Summary: He was the 3rd pope (bishop of Rome) after Saint Peter. He wrote some of the earliest Christian letters and documents after Gospels and the New Testament. He emphasized the importance of Apostolic succession and church authority. He was a highly respected leader within the early church, and some of his letters were even read as scripture for the first few centuries. His book was one of the closest books not to have made it officially into the biblical canon.

Ignatius of Antioch

Theological Legacy: Pioneer of Ecclesiology
Dates: 35-108
Location: Antioch, Syria (modern day Antakya, Turkey)
Position: Bishop of Antioch
Influenced by: Apostolic Tradition, John the Apostle, early disciples and companions of the apostles
Key Concepts:

Unity of the Church
Authority of bishops
Divinity and humanity of Christ
The Eucharist as the body and blood of Christ
Opposition to heresy

Major Works:

Epistles to Ephesians, Magnesians, Trallian, Romans, Philadelphians, Smyrneans, Polycarp

Influenced: Polycarp of Smyrna, Irenaeus
Titles/Honors: Saint, Apostolic Father, Chuch Father, Martyr
Canonized: Pre Congregation
Summary: An early Apostolic Father and bishop from Antioch who was very influential in uniting the church. His final letters (epistles) leading up to his execution became foundational Christian teachings. This included teachings on the unity of the church, episcopal hierarchy, the Eucharist, and divinity of Christ. He was arrested during the reign of Roman Emperor Trajan and transported to Rome to be martyred by wild beasts in the arena.

Simon Magus

Theological Legacy: First Heretic and Father of Simony
Dates: 1st century
Location: Samaria, (Roman Judea)
Position: Magician, religious teacher
Influenced by: Samaritan religious traditions
Key Concepts:

Pursuit of secret spiritual knowledge (Gnosticism)
Religious syncretism
Spiritual authority and power
Self-exaltation and divine statue

Major Works: No written works, but he is mentioned in the Acts of the Apostles
Influenced: Simonians, Later Gnostic traditions.
Titles/Honors: Founder of Simonians
Canonized: No (Deemed a heretic)
Summary: He was famous for his open theological debates with Saint Peter, which often included miracle duels according to legend. He was known as a magician, a passionate orator, and teacher. He is considered the father of Gnosticism. He is considered the first Christian heretic and rival, often labeled as the "Bad Samaritan". The crime of buying or selling of spiritual authority is referred to as "simony" since he tried to buy church authority from Peter and Paul.

Papias of Hierapolis

Theological Legacy: Pioneer of Apostolic Tradition
Dates: 60-130
Location: Hierapolis, Phrygia (modern-day Turkey)
Position: Bishop of Hierapolis
Influenced by: Apostolic Tradition, Companions and disciples of the apostles
Key Concepts:

Preservation of Apostolic Tradition
Early Gospel writings
Establishment of Oral tradition
Chiliasm- Christ will return and establish a thousand year reign

Major Works:

Exposition of the Sayings from the Lord (5-Volume book)

Influenced: Irenaeus, Eusebius
Titles/Honors: Saint, Apostolic Father
Canonized: Pre-congregation
Summary: He was best known for gathering and writing many of the early apostolic traditions and stories of Jesus. He is considered one of the earliest Christian writers and theologians pertaining to the apostolic tradition and the origins of the Gospel. His most famous work included the famous sayings of Jesus Christ, the Apostles, and interpretations of Christian teachings.

Polycarp of Smyrna

Theological Legacy: Defender of Apostolic Tradition
Dates: 69-155
Location: Smyrna, Asia Minor (modern day Izmir, Turkey)
Position: Bishop of Smyrna
Influenced by: Apostolic Tradition, John the Apostle, early disciples and companions of the apostles
Key Concepts:

Preservation of apostolic teaching
Church unity
Defense of Christian doctrine in the face of persecution

Major Works:

The Epistle to the Philippians

Influenced: Irenaeus of Lyons
Titles/Honors: Saint, Apostolic Father, Martyr
Canonized: Pre congregation
Summary: He was a follower of the Apostle John, who became bishop and one of the most important early church fathers. He was especially devoted to church unity and preserving the apostolic teachings, which brought him at odds with the Roman authorities. He was burnt at the staked and killed by spear for refusing to renounce Christianity. His martyrdom went on to further strengthen the Christian movement and inspire some of the most important theologians such as Irenaeus of Lyons.

2nd century - The Apologists & Gnostics

Quadratus of Athens

Theological Legacy: Pioneer of Christian Apologetics
Dates: 1st century- 129
Location: Athens, Greece
Position: Bishop of Athens, Apologist
Influenced by: Apostolic tradition, Early Christian disciples and community
Key Concepts:

Defense of Christian culture against Paganism (Apologetics)
Historical reliability of Jesus' miracles
Eyewitness testimonies
Christianity as a historical religion with real events

Major Works:

Apology to Emperor Hadrian

Influenced: Aristides of Athens, Justin Martyr
Titles/Honors: Saint, Apostolic father, Apologist
Canonized: Pre-Congregation
Summary: He is considered one of the first of the Christian apologetics who defended Christianity against the Roman Pagan rulers. He gathered historical accounts and real testimonies from witnesses of the miracles and life of Jesus Christ to further strengthen the credibility of Christianity. The term "apology" in this sense does not mean being sorry, rather it is justification or legal defense of one's beliefs. According to legend Quadratus was eventually imprisoned for his preaching to the pagans and beheads by the Roman authorities.

Aristides the Athenian

Theological Legacy: Advocate of Christian Apologetics
Dates: 1st century- 140
Location: Athens, Greece
Position: Christian Apologist
Influenced by: Greek philosophy, Apostolic tradition
Key Concepts:

Monotheism
Rational defense of Christianity
Moral superiority of Christianity
Critique on pagan religions

Major Works:

Apology of Aristides

Influenced: Justin Martyr, Athenagoras
Titles/Honors: Saint, Apologist
Canonized: Pre-Congregation
Summary: He was an important early Christian apologist who defended the faith thru academic claims. He used his knowledge of Greek philosophy to explain the true nature of Christianity versus other pagan religions. His apology (defense of the faith) is considered one of the earliest cases made to the Roman emperor.

Marcion of Sinope

Theological Legacy: Father of Christian Dualism
Dates: 85-160
Location: Sinope, Pontus (modern day Turkey)
Position: Christian theologian, founder of Marcionism
Influenced by: Paul the Apostle, Cerdo
Key Concepts:

Dualism (two supreme deities; Good and Evil)
Rejection of Judaism and the Old Testament
Salvation thru the God of the New Testament
Primacy of Paul

Major Works:

Antitheses
Gospel of Marcion
Marcionite Canon
Gospel of Marcion
10 Pauline Epistles

Influenced: Marcionism, Irenaeus, Tertullian
Titles/Honors: Founder of Marcionism
Canonized: No. Deemed a heretic.
Summary: He was a very influential and controversial theologian who presented strong cases for the church to debate on. This included a well defined biblical canon that rejected the Old Testament and Jewish practices. Marcion sought to cut the ties with the old Jewish faith, seeing their God as different from the God of Jesus Christ and the New Testament. He is also considered one of the early founders of Christian dualism theory.

Justin Martyr

Theological Legacy: Philosopher of the Logos
Dates: 100-165
Location: Flavia Neapolis, Samaria (modern Nablus, West Bank Palestine)
Position: Christian Apologist, Philosopher
Influenced by: Platonism, Socrates, Greek philosophy, Apostolic Tradition
Key Concepts:

Christianity as the true philosophy
Logo theology (The pre-existent nature of Christ as the eternal word of God; the second person in the Trinity)
Harmony of faith and reason
Christ's fulfillment of the prophecies of the Old Testament
Defense of Christianity and critique of Pagan religions
Moral superiority of Christianity

Major Works:

First Apology
Second Apology
Dialogue with Trypho
Against Marcion
Against All Heresies

Influenced: Irenaeus of Lyons, Clement of Alexandria, Origen
Titles/Honors: Saint, Apologist, Martyr
Canonized: Pre-congregation
Summary: He was a philosopher who converted to Christianity and one of the early apologists who defended the faith. He used his knowledge of Plato, Socrates, and Greek Philosophy to bridge the gap of Christian reason. He argued in favor of Christ's moral superiority over other religions and especially promoted the concept of the logos. He was famously martyred in public alongside his companions by the Roman prefect Junius Rusticus. Once Justin and his followers refused to renounce their faith and sacrifice to the Roman gods, they were scourged and beheaded.

Valentinus of Rome

Theological Legacy: Architect of Gnosticism
Dates: 100-165
Location: Rome, Roman Empire
Position: Theologian, Gnostic teacher, founder of the Valentinian school
Influenced by: Platonism, Alexandrian Christianity, Theudas
Key Concepts:

Gnosis (study of secret knowledge)
The Pleroma (fullness of divine reality)
Aeons (Divine beings that flowed out from God; approx 30 including Jesus Christ)
The Fall of Sophia (Wisdom) due to approaching God. This lead to the lower material realm of the universe as we know it.
Three types of humanity; spiritual, psychic, and material
Salvation through awakening to divine knowledge

Major Works:

Gospel of Truth

Influenced: Valentinianism, Ptolemy, Heracleon
Titles/Honors: Founder of Valentinianism
Canonized: No. Deemed a heretic.
Summary: Considered one of the fathers of Gnosticism, who established the theological branch of Valentinianism. This grew into a rival Christian sect that was centered on secret spiritual knowledge (referred to as gnosis). His philosophy was eventually rejected by the church as heresy.

Melito of Sardis

Theological Legacy: Pioneer of Paschal Theology
Dates: 100-180
Location: Sardis, Lydia (Asia Minor, modern day Turkey)
Position: Bishop of Sardis, Apologist, Theologian
Influenced by: Johannine Christianity, Apostolic tradition
Key Concepts:

Christ as the fulfillment of the Old Testament
Typology (Old Testament foreshadowing of the coming of Christ)
Unity of Old Testament and New Testament
Defense of Christianity
Biblical canon
Christology (Jesus as both God and man)

Major Works:

Peri Pascha
Apology to Marcus Aurelius
Extracts
Treatises on Faith, the Church, Creation, the Lords Day, and Revelation

Influenced: Irenaeus of Lyons
Titles/Honors: Saint, Apologist
Canonized: Pre Congregation Saint
Summary: One of the strongest early advocates for the unity between the Old Testament and the New Testament. He saw the Old Testament as a necessary prequel to the Christian faith due to it's prophecies and fulfillment of the Jewish Passover. He also famously defended the Christian faith in his apology to Marcus Aurelius. He produced one of the earliest documented lists of the Old Testament which made up the basis of the biblical canon.

Hegesippus

Theological Legacy: Archivist of Church History
Dates: 110-180
Location: Palestine, Jerusalem, Corinth, Rome
Position: Church historian, chronicler
Influenced by: Apostolic tradition, Jewish Christianity
Key Concepts:

Apostolic succession
Preservation of traditional doctrine
Church unity
Opposition to Gnosticism
Historical credibility of the Apostolic tradition and the church

Major Works:

Hypomnemata

Influenced: Eusebius of Caesarea
Titles/Honors: Saint
Canonized: Pre-Congregation Saint
Summary: He was a key figure in preserving the early church thru written historical accounts. He was known for his travels across Palestine, Jerusalem, Corinth, and Rome investigating all the structures of their Christian churches. He especially promoted the unity of the church across all regions and spoke harshly against Gnosticism and heresy.

Athenagoras of Athens

Theological Legacy: Philosopher of Christian Apologetics
Dates: 115-190
Location: Athens, Greece
Position: Christian Apologist
Influenced by: Platonism, Greek philosophy
Key Concepts:

Harmony of faith and reason
Monotheism
Defense of Christians against persecutions
The Trinity
Resurrection of the body
Christian morality
Critique of pagan idolatry

Major Works:

A Plea for the Christians
On the Resurrection of the Dead
Influenced: Alexandrian Christianity

Titles/Honors: Saint, Apologist
Canonized: Pre-congregation, saint
Summary: He defended the Christian faith in his apology to Marcus Aurelius and Commodus. He fought against false claims of atheism, cannibalism, and immorality. Athenagoras also claimed Christianity was the one true rational faith while the other religions were false pagan idolatry. He also promoted the concept of the Trinity as well as the resurrection of the human body (and not just the soul).

Dionysius of Corinth

Theological Legacy: Defender Against Heresy
Dates: 1st century- 175
Location: Corinth, Achaia (Greece)
Position: Bishop of Corinth, theologian
Influenced by: Apostolic Tradition
Key Concepts:

Church Unity
Orthodoxy against heresy
Pastoral care
Apostolic tradition
Charity toward sinners and penitents
Marriage and continence
Inter church cooperation

Major Works:

Letters to the Romans, Athenians, Nicomedians, Churches of Crete, Pontus, Cnossians, Chysophora

Influenced: Eusebius of Caesarea
Titles/Honors: Saint
Canonized: Yes. Pre Congregation saint
Summary: Bishop of Corinth known for his many letters to churches across the Mediterranean region encouraging church unity and cooperation. Dionysius promoted the importance of the clergy's role as well practicing charity and showing forgiveness to sinners and penitents. He spoke out against heresies such as Marcionism and defended the Orthodox church as the one true Christian church.

Heracleon

Theological Legacy: Advocate of Valentianism-Gnosticism
Dates: 1st century- 180
Location: Alexandria, Egypt
Position: Valentinian Gnostic Theologian
Influenced by: Valentinus, Valentinian Gnosticism, Alexandrian Christianity, Greek philosophy
Key Concepts:

Gnosis (secret knowledge)
Valentinian theology
Allegorical interpretation of scripture
Distinction between spiritual, psychic, and material persons
Pleroma and Aeons (fullness of God with divine beings that proceed thru him)
Salvation thru revealed knowledge

Major Works: Commentary on the Gospel of John and New Testament writings
Influenced: Origen, Gnostic interpretations
Titles/Honors: Leading Valentinian teachers
Canonized: No. Deemed a heretic
Summary: He was a devoted disciple of Valentinian, an adherent to the belief of Gnosticism. He interpreted many of the New Testament books, most notably the Gospel of John, thru his gnostic viewpoints. His unique perspectives influenced many Gnostic, philosophical, and even Christian thinkers such as Origen.

Basilides

Theological Legacy: Philosopher of Gnostic Cosmology
Dates: 117-161
Location: Alexandria, Egypt
Position: Gnostic Christian teacher, founder of Basilidian school
Influenced by: Alexandrian Christianity, Platonism, Hellenistic philosophy, Menander
Key Concepts:

Gnosis
God as the transcendent source of reality
Multiple heavens
Divine beings that flowed from God (mind, word, truth, life, wisdom, church, humanity)
Creation and the problem of evil
The spiritual liberation of the soul
The concept of Abraxas (highest cosmic power and ruler of the heavens).

Major Works: Exegetica (24 volume commentary on the gospels), Psalms and Odes
Influenced: Bisamidinium
Titles/Honors: Founder of Basilidianism
Canonized: No. Deemed a heretic.
Summary: Another influential Gnostic teacher who established his own Christian sect referred to as Basilidianism. His philosophy was a very cosmic one, which consisted of multiple heavens and multiple divine beings that flowed from God. As with all gnostic beliefs, that main pursuit was in obtaining secret spiritual knowledge to achieve liberation of the soul.

Irenaeus of Lyon

Theological Legacy: First Doctor of Christian Orthodoxy
Dates: 130-202
Location: Smyrna (Asia Minor, modern day Turkey)- Lyons, Gaul (modern day France)
Position: Bishop of Lyons, Theologian, Apologist
Influenced by: Polycarp of Smyrna, John the Apostle, Justin Martyr, Apostolic Tradition
Key Concepts:

Authority of scripture, apostolic succession, and tradition
Rule of faith
Opposition to Gnosticism
Unity of the Old and New Testament
The four gospel canon
Recapitulation (Christ as the new Adam, representing God's new covenant with humanity)
Creation as an act of good and love (against Gnosticism and dualist theories)

Major Works:

Adversus Haereses
Demonstration of the Apostolic Preaching
On the Ogdoad
On Knowledge
Various letters and treaties

Influenced: Tertullian, Hippolytus, Augustine of Hippo, Basil the Great
Titles/Honors: Saint, Church Father, Doctor of the Church
Canonized: Yes. Pre congregation saint
Summary: He is considered one of the most important Christian theologians of the second century with many significant contributions. He was the perfect example of the apostolic succession, as a disciple of Polycarp, who was a disciple of John the Apostle, who was an apostle of Jesus Christ. Irenaeus was a strong defender of the faith and the authority of the church structure. He also was a chief opponent against the sect of Gnosticism and other heresies. Irenaeus went on to influence many more great theologians and he is honored as the first Doctor of the Church.

Bardaisan

Theological Legacy: Rejection of Fatalism
Dates: 154-222
Location: Edessa, Osrhoene (Turkey/Syria)
Position: Christian Theologian, Poet, Scholar
Influenced by: Syriac Christianity, Middle Platonism, Astrology, Mesopotamian thought
Key Concepts:

Free will vs fate
Critique of astrological determinism (against the notion of the stars determining our fates)
Human moral responsibility
Cosmology (Cosmic powers and supernatural elements)
Early Syriac Christian Theology

Major Works:

Book of the Laws of Countries, many hymns and poems

Influenced: Syriac Christianity, Ephrem the Syrian, Eastern Christianity
Titles/Honors: Founding father of the Bardaisanite movement and Syriac Christianity
Canonized: No. Deemed a heretic
Summary: He is considered one of the founders of Eastern Syriac Christianity who influenced the great Ephraim the Syrian. Bardaisan blended cosmology and philosophy into Christian theology. He was one of the early advocates against free will and any form of astrology and fatalism. He is considered controversial and even deemed a heretic for his views in favor of the cosmos and the stars. Even though he supports free will and the authority of God, he still puts far too much emphasis on the metaphysical role of cosmology.

Tertullian

Theological Legacy: Architect of Trinitarian theology
Dates: 155-220
Location: Carthage, Roman North Africa (modern Tunisia)
Position: Theologian, Apologist, Polemicist
Influenced by: Roman laws, Stoic philosophy, North African Christianity
Key Concepts:

The Trinity (One substance, three persons)
Apostolic tradition
Rule of faith (more rigor and discipline)
Religious liberty
Opposition to Gnosticism and Marcionism

Major Works:

Apologeticus
Against Marcion
Prescription Against Heretics
Against Praxeas
On Baptism
On the Flesh of Christ
On the Resurrection of the Flesh

Influenced: Cyprian of Carthage, Augustine of Hippo
Titles/Honors: Apologist, Founder of Western Theology
Canonized: No
Summary: Considered the first great Latin Christian writer and influential theologian of the Western Church. Tertullian defended Christianity against Roman pagans and opposed the heretical movements of Gnosticism and Marcionism. He was an early advocate of the concept of the Trinity and helped define the terminology of the three persons of God. However he was later deemed as controversial due to influence on the movement of Montanism, which held that the Holy Spirit was still speaking thru prophets.

Origen of Alexandria

Theological Legacy: Architect of Christian Exegesis
Dates: 185-253
Location: Alexandria, Egypt; Caesarea, Palestine
Position: Theologian, Apologist, Head of School of Alexandria
Influenced by: Clement of Alexandria, Platonism, Ammonius Saccas, Alexandrian Christianity
Key Concepts:

Allegorical interpretation of Scripture
Free will
Logos theology
Biblical interpretation and criticism
Apokatastasis (universal restoration, against eternal hell)
Pre-existence of souls
Threefold sense of scirpture (body, soul, spirit)

Major Works:

On First Principles
Contra Celsum
Hexapla
Commentary on John
Commentary on Matthew
Influenced: Gregory Thaumaturgas, Athanasius, Basil the Great, Gregory of Nyssa, Jerome, Ambrose

Major Opponents: Methodius of Olympus, Epiphanius of Salamis, Jerome, Theophilus of Alexandria, Emperor Justinian
Titles/Honors: Father of Christian Exegesis
Canonized: No.
Summary: He is considered one of the greatest Christian scholars of the Early Church. His interpretations of the bible were quite groundbreaking, which defined many allegorical themes and helped establish a systematic theological doctrine. Despite his influential role in early Christian philosophy he was ultimately deemed controversial for some of his viewpoints pertaining to castration, pre-existence, and Apokatastasis. Nonetheless he went on to influence many great Christian thinkers and I for one somewhat agree with his concepts of pre-existence and the forgiveness of all souls. I also like his concept that it is the spirit that goes on after life, and not so much the physical body (even though I do like the concept of the Last Judgement and a New Jerusalem where our bodies are reunited with our souls). Many of his concepts were accepted by the church for nearly 200 years before they were attacked during the Origensist Crisis. It's still fair to say that although some of his ideas were rejected he still made great contributions to the early development of Christian theology. He influenced some of the greatest church doctors such as Athanasius, Basil the great, and Gregory of Nyssa.

Sabellius

Theological Legacy: Founder of Modalism
Dates: 2nd century- 220
Location: Rome, Roman Empire
Position: Theologian, leader of Sabellianism movement
Influenced by: Noetus, and anti-Trinitarian concepts
Key Concepts:

Modalistic Monarchianism (Sabellianism)- God is one person and not three persons
Father, Son, and Holy Spirit are different roles of the one God
Divine unity of God's roles as father, son, and holy spirit
Influenced: Later Modalist movements

Major Opponents: Hippolytus of Rome
Titles/Honors: Founder of Sabellianism/Modalism
Canonized: No. Deemed a heretic
Summary: He was an influential theologian who promoted beliefs of monarchism against the concept of the Trinity. He taught that God was one distinct person in the form of Father, Son, and Holy Spirit and NOT three persons as believed in the Trinity. Sabellius saw God as three roles and manifestations, but not three distinct persons. His teachings eventually gained traction and become known as Sabellianism. He was eventually deemed a heretic and excommunicated for his teachings. However this anti-Trinitarian debate went on for many years in the form of Monarchianism, Adoptionism, and Arianism.

3rd century - The Trinitarian Question

Hippolytus of Rome

Theological Legacy: Defender of Trinitarian Theology
Dates: 170-235
Location: Rome, Roman Empire
Position: Theologian, Regarded as the first antipope
Influenced by: Irenaeus of Lyons
Key Concepts:

Defense of Trinitarian theology
Against Modalism/Sabellianism and other heresies
Apostolic church order and liturgy
Biblical exegesis and eschatology
Strict Christian discipline and morality

Major Works:

Refutation of All Heresies
Apostolic Tradition
Commentary on Daniel
On Christ and the Antichrist
Influenced: Early Christian theology

Major Opponents: Sabellius
Titles/Honors: Saint, Church Father, Martyr
Canonized: Yes. Pre-Congregation
Summary: He was an influential theologian and church father who defended orthodox Christianity against heresies such as Modalism and Sabellianism (that viewed God as one disctint person with three different roles). He also made great contributions at interpreting the bible and establishing church structure, discipline, and order. He is considered the first antipope, when he broke with the church of Rome and declared himself bishop for 19 years. He was later arrested and exiled to the mines of Sardina by the Christian persecutions of Emperor Maximinus. During his enslavement he made peace with his rival Pope Pontian, and encouraged his followers to reunite with the Roman Church. He was later martyred for his belief in Christ. He is one of the rare antipopes, who is canonized as a saint.

Dionysius of Alexandria

Theological Legacy: Pioneer of Trinitarian theology
Dates: 190-264
Location: Alexandria, Egypt
Position: Bishop of Alexandria
Influenced by: Origen, Clement of Alexandria
Key Concepts:

Defense of Trinitarian belief
Rejection of Sabellianism and millenarian/chiliasm interpretations
Pastoral moderation in church discipline
Emphasis on the distinction of the Father and the Son, while still recognizing their unity as the same God
Careful biblical interpretation (balance of reading it literally but also allegorically)

Major Works:

On the Promises
Refutation and Defense
Influenced: Athanasius of Alexandria

Major Opponents: Sabellians, Novatianist movement
Titles/Honors: Church Father, Saint
Canonized: Yes. Pre-congregation saint.
Summary: Often referred to as Dionysius the Great, was one of the great early church fathers who helped shape the church doctrine. He was a student of Origen and led Christians in Alexandria during the periods of persecution. He preserved church unity, defended those who had lapsed, was against rebaptism, and fought against the Novatianist movement. He was considered a key theologian in developing the Trinity belief that was officially formulated at the Nicaea Council. He also promoted proper biblical interpretation, emphasizing a balance of symbolism and literalism.

Cyprian of Carthage

Theological Legacy: Architect of Ecclesiology
Dates: 200-258
Location: Carthage, North Africa (modern Day Tunis, Tunisia)
Position: Bishop of Carthage
Influenced by: Tertullian
Key Concepts:

Unity of the church
Authority of the bishops
Christian discipline and repentance
Defense of Christians during persecution
Ecclesiastical communion

Major Works:

On the Unity of the Catholic Church
On the Lapsed
On Mortality

Influenced: St. Augustine of Hippo
Major Opponents: Novatian (against those who had lapsed or committed apostasy), Felicissimus (restoration without repentance)
Titles/Honors: Saint, Church Father, Martyr
Canonized: Yes. Pre Congregation Saint
Summary: He is regarded as one of the most important early church fathers, who helped shape Christian doctrine and unity. He lived during heavy Roman persecutions and decided to go into hiding during the persecutions under Emperor Decian. He did this not out of fear yet rather for the survival of the church, since he was such an important figure. Nonetheless Cyprian faced heavy criticism from other prominent Christian leaders for not standing up for his faith. Cyprian did favor repentance for the lapsed but also restoration for any clergy members. He later got a second chance to prove his honor, and this time he did not flee during the persecution under Valerian who had him martyred for his beliefs.

Paul of Samosata

Theological Legacy: Advocate of Adoptionism
Dates: 200-275
Location: Samosata (Syria region); Antioch (modern day Antakya, Turkey)
Position: Bishop of Antioch
Influenced by: Monarchianism, Adoptionism
Key Concepts:

Strong emphasis on the oneness of God (Monarchianism)
Jesus was not an eternal being, rather a human who inherited the divine power of God
Rejection of Trinitarian and Logos theology, that considered Jesus as the Son of God, long before he became human.

Influenced: The Paulianist Movement
Major Opponents: Malchion, Dionysius of Alexandria
Titles/Honors: Founder of the Paulinist Movement
Canonized: No. Deemed as a heretic.
Summary: An influential bishop of Antioch who favored the concepts of Monarchianism and Adoptionism against the belief of Trinitarianism. He strongly rejected that Christ was an eternal being long before he became human. His beliefs led to major debate and synod councils to further address the theological disagreement. His bishop status was eventually revoked by the Church, however he retained control of his church thru the protection of Queen Zenobia of Palmyra. Eventually the Roman Church got Emperor Aurelian to intercede on the matter and officially remove him from his post. The Paulinist Movement further added fuel to the burning disagreement over the Trinity. It had already ignited over the Sabellius movement and continued to grow eventually into the much larger Arian Movement. Eventually the matter was addressed and closed at the first ecumenical council at Nicaea in 325.

Novatian

Theological Legacy: Advocate of Rigorism
Dates: 200-258
Location: Rome, Roman Empire
Position: Priest in Rome, Antipope during the Novatianist Schism (first major schism)
Influenced by: Tertullian
Key Concepts:

The church should be a communion of pure faithful members (and not those who lapsed in the face of persecution)
Zero tolerance for Christians who apostatized during persecution (especially for clergy leaders)
Strong opposition to any form of leniency towards the lapsed
Advocate of the Trinity

Major Works:

On the Trinity
On Public Shows
On Jewish Foods
Influenced: Novatianist Movement

Major Opponents: Pope Cornelius of Rome, Cyprian of Carthage
Titles/Honors: Leader of the Novatianist Movement
Canonized: No. Considered a Schismatic
Summary: He was one of the harshest theologians on those who had lapsed or committed a form of apostasy during Roman persecutions. He famously declared himself antipope when Cornelius became pope in 251. He strongly argued that those who committed apostasy should not be restored to the church, especially clergy leaders. Many argued against this harsh stance, defending those who had lapsed as extreme measures of survival. Prominent church leaders such as Cyprian argued the lapsed should be allowed back to the church thru repentance. Nonetheless Novatian stood by his strict beliefs, and gathered a followed, which led to the first major schism in the Christian Church.

Gregory Thaumaturgus

Theological Legacy: Pioneer of Christian Hellenism
Dates: 213-275
Location: Pontus in Asia Minor (northeastern Turkey)
Position: Bishop of Neocaesarea
Influenced by: Origen
Key Concepts:

Defense of Trinitarian doctrine
Merging of Christian theology with Greek philosophy (Hellenism)
Missionary campaigns of pastoral leadership
The miraculous power of God working thru the church
Emphasis on divine providence and Christian holiness

Major Works:

Oration and Panegyric Addressed to Origen
Declaration of Faith
Canonical Epistle

Influenced: Basil the Great, Gregory of Nyssa, Cappadocian Fathers
Major Opponents: Pagan religion in Pontus
Titles/Honors: Saint Gregory the Wonderworker, Church Father
Canonized: Yes. Pre Congregation saint
Summary: He was a disciple of Origen and a student of Greek Philosophy who used his knowledge to further advance Christian theology. He later became bishop of Neocaesarea where he greatly contributed to the spread of Christianity in the region thru his missionary work. He is also credited with many miracles throughout his evangelization travels, which brought him the title, Gregory the Wonderworker. He was a strong advocate for the distinction and unity of the Father, Son, and Holy Spirit. He helped bridge the gap between Greek Philosophy and Christian Theology which became foundational concepts that later influenced the Cappadocian Fathers and the Nicaea Council.

Lucian of Antioch

Theological Legacy: Advocate of Literal Exegesis
Dates: 240-312
Location: Antioch, Syria (modern Antakya, Turkey)
Position: Presbyter of Antioch, Theologian
Influenced by: Paul of Samosata, Antiochene tradition
Key Concepts:

Belief in the literal and historical interpretation of the bible
Critique of allegorical interpretations
Strong distinction between the Father and the Son

Major Works:

Revision of the Greek Septuagint text
Theological teratises and letters

Influenced: Arian movement, Eusebius of Nicomedia, Diodore of Tarsus, Theodore of Mopsuestia
Major Opponents: Roman Pagan persecutors, allegorical interpretation
Titles/Honors: Saint, Martyr
Canonized: Yes. Pre congregation saint
Summary: He was an influential priest and head teacher at the theological school of Antioch. His claim to fame was his defense of the literal approach to biblical interpretation against the symbolic approach. This favored historical and grammatical reasoning against the allegorical school of Alexandria such as Origen and Dionysius. Lucian stressed the distinction between the Father and the Son, emphasizing that the son was subordinate to the father. This was not to be confused with Arianism however which believed there was a time where the Son was not. Lucian was later imprisoned and martyred during the Roman Persecutions of 311-312.

Methodius of Olympus

Theological Legacy: Defender of Bodily Resurrection
Dates: 250-311
Location: Olympus in Lycia (Asia minor, modern Turkey)
Position: Bishop of Olympus, Theologian
Influenced by: Irenaeus of Lyons
Key Concepts:

Defense of Bodily Resurrection
Critique of certain teachings of Origen (such as pre-existence and Apokatastasis)
Promotion of Virginity and Christian asceticism
Against Gnosticism
Free Will over Determinism
The goodness of God and Creation (against the notions of Dualism)
Christ as the fulfillment of Old Testament prophecies
Spiritual growth and participation in divine life

Major Works:

The Banquet of the Ten Virgins
On the Resurrection
On Free Will
On Created Things
On Life and Rational Action

Influenced: Epiphanius of Salamis, anti-Origenist theology
Major Opponents: Followers of Origen, Gnostic believers
Titles/Honors: Saint, Church Father, Martyr
Canonized: Yes. Pre-Congregation Saint
Summary: Methodius is considered one of the early critics of Origen, especially against his concepts of pre-existence and salvation for all souls. He also promoted the concept of bodily resurrection instead of just spiritual resurrection. This is the reason he rejected pre-existence since he believed our lives began with our physical bodies and not some pre-existing spirit. His most famous work, The Banquet of the Ten Virgins, was based off Plato's Symposium, as a dialogue among Christians praising their virginity and holiness. He was an advocate for free will over the concepts of determinism where everything was a product of previous events. It is believed he was martyred during the Roman-Christian persecutions of 311 near Chalcis, Greece.

Lactantius

Theological Legacy: Critic of Roman Paganism
Dates: 250-325
Location: Numidia, North Africa
Position: Apologist, Theologian
Influenced by: Cicero, Roman and Platonic Philosophy
Key Concepts:

Defend Christianity against Pagan religions
Divine justice, providence, and free will
The immortality of the soul
The superiority of Christianity over Greco-Roman religion
Belief in Chiliasm (1000 year kingdom of Jesus prior to Final Judgement)
The transformation of society thru Christianity

Major Works:

Divine Institutes
On the Deaths of the Persecutors
On the Workmanship of God
Epitome of the Divine Institutes
Influenced: Western Christian Theology

Major Opponents: Pagan religion, Polytheism, Skepticism
Titles/Honors: Apologist
Canonized: No.
Summary: One of the most important Western/Latin Christian writers who infused Roman and Platonic Philosophy into Christianity. He presented Christianity as the true rational religion as opposed to the mythical belief of polytheistic Pagan gods. He also defended the concepts of free will, immortality of the soul, and the final judgement of humanity. Lactantius believed in the chiliasm theory that Jesus would return to establish a 1000 year kingdom on Earth before the Final Judgement. He also predicted the downfall of the Roman Empire due to it's persecutions of Christians. Thru his well-written defense of the Christian faith against Roman pagans, he is considered one of the great Apologists, often referred to as "The Christian Cicero". Despite his great writings in defense of the church, he was not canonized because some of his concepts were considered questionable such as chiliasm and subordinationism.

Alexander of Alexandria

Theological Legacy: Opponent of Arianism
Dates: 250-326
Location: Alexandria, Egypt
Position: Bishop/Patriarch of Alexandria
Influenced by: Alexandrian tradition, Dionysius of Alexandria
Key Concepts:

Defense of Christ's full divinity
Eternity of the Son
Opposition to Arianism
Preservation of apostolic doctrine
Unity of the church against schism and heresy

Major Works:

Letters against Arianism
Epistle to Alexander of Constantinople
Treatise concerning the date of Easter

Influenced: Athanasius of Alexandria, Nicene movement
Major Opponents: Arius, Meletius of Lycopolis
Titles/Honors: Saint
Canonized: Yes. Pre congregation
Summary: He was one of Arius' fiercest rivals against his movement of Arianism that rejected the Trinity. Alexander was a key figure at the Council of Nicaea who spoke in defense of the Trinity, holding that Jesus was eternal and truly divine. He also played a significant role in mentoring the great Athanasius of Alexandria, who would become one of the great early doctors of the church. He is regarded as an important voice at the Nicaea Council that helped preserve the Trinity as we know it today.

Arnobius of Sicca

Theological Legacy: Apologist against Paganism
Dates: 255-330
Location: Sicca Veneria, Roman North Africa (modern El Kef, Tunisia)
Position: Christian apologist
Influenced by: Roman rhetoric, Platonism
Key Concepts:

Defense of Christianity as the Superior religion; against pagans
Critique of Greco-Roman religion and mythology
Rejection of idolatry and temple worship
Divine transcendence
Immorality as a gift from God, rather a property of the soul

Major Works:

Against the Pagans- seven book Apologetic writing during the Diocletian persecutions

Influenced: Lactantius
Major Opponents: Pagan leaders, Polytheism
Titles/Honors: Early Christian Apologist
Canonized: No. Not deemed heretical but some of his views went against Orthodox teaching
Summary: He was an apologist and rhetorician who specialized in critiques against the Roman And Greek pagan rituals. He emphasized the Christian religion was the superior form of worship, and that idolatry and temple worship was a form of false mythology. Arnobius also emphasized that the soul is not an automatic eternal essence, rather immortality can only come thru Salvation of God. Many of his writings came during the Diocletian persecutions when Christianity was still not officially legal in the Roman Empire. Despite his great contribution to the church as a defender of the faith, some of his views were later rejected by the church as heretical. Mostly his concept that the soul was not immortal, but could only become mortal thru salvation. This was against Orthodox teaching that every soul was eternal and would proceed to heaven or hell.

Arius of Alexandria

Theological Legacy: Advocate of Subordinationism
Dates: 256-336
Location: Alexandria, Egypt
Position: Presbyter and theologian of Alexandria
Influenced by: Lucian of Antioch
Key Concepts:

Defender of Arianism
The Son was Created by the Father
The Son was not co-eternal with the father
"There was a time when the son was not"
Emphasis on the uniqueness and supremacy of God the Father

Major Works:

Thalia
Various letters and hymns

Influenced: Arian Christians, Eusebius of Nicomedia
Major Opponents: Alexander of Alexandria, Athanasius of Alexandria
Titles/Honors: Founder of Arianism
Canonized: No. Deemed a heretic
Summary: He was a priest from Alexandria, whose teachings about Christ and God sparked the Arian Controversy. He expanded on Lucian's concept of Jesus as being subordinate to God by claiming that Jesus was created by God the Father, and was not co-eternal. This went against accepted Church doctrine that held Jesus was begotten of the same substance as God. Arianism gained a major following with it's central belief that "There was a time when the son was not". This debate became one of the main topics at the First Council of Nicaea convoked by Emperor Constantine in 325. Arius' concepts were ultimately deemed heretical however many continued to believe in Arianism for centuries to come (including kings and emperors).

Aphrahat the Persian Sage

Theological Legacy: Pioneer of Syriac Asceticism
Dates: 280-345
Location: Sasanian Empire (Persian Empire)
Position: Syriac Christian Author
Influenced by: Sons of the Covenant movement, Syriac Christian tradition
Key Concepts:

Biblical literalist rather than philosophical or allegorical interpretation
Faith, prayer, fasting, humility, and charity
Practice of asceticism and celibacy
Christology and ecclesiology in Syriac tradition
Relationship between Christianity and Judaism

Major Works:

The Demonstrations- 23 homilies/treatises on Christian doctrine and practice

Influenced: Later Syriac Christianity, The Church of the East
Major Opponents: Judaizing Christians
Titles/Honors: The Persian Sage
Canonized: Yes. Pre Congregation saint
Summary: He is referred to as the Persian Sage for his many theological contributions to the Syriac Church and the Church of the East. Aphrahat emphasized the ascetic practices of fasting, prayer, celibacy, and humility. He also promoted the approach of literal biblical interpretation versus allegorical meanings. His famous work, the Demonstrations, lay out an early foundation for the Syrian Christian church that would later evolve into the Church of the East.

Athanasius of Alexandria

Theological Legacy: Architect of the Nicene Trinity
Dates: 296-373
Location: Alexandria, Roman Egypt
Position: Deacon under Alexander of Alexandria
Influenced by: Alexander of Alexandria, Anthony the Great, Origen
Key Concepts:

Defense of the fully divinity of Christ
Homoousios belief- that Jesus was of the same substances as the father
The Holy Trinity
Incarnation and salvation
Opposition to Arianism
Support of Christian monasticism

Major Works:

On the Incarnation
Against the Heathen
Life of Antony
Four Orations Against the Arians
Letters to Serapion
Festal Letters
Influenced: Basil the Great, Gregory of Nazianzus, Gregory of Nyssa

Major Opponents: Arius, Eusebius of Nicomedia
Titles/Honors: Father of Orthodoxy, Church father, Doctor of the Church, Saint
Canonized: Yes. Pre Congregation saint
Summary: Considered one of the great early doctors of the church, he was the key champion against Arianism at the Council of Nicaea. He fervently defended the Holy Trinity, and the concept of Jesus' divinity and co-eternal being with the father. He lead the council against Arius' concepts in which there was a time where the son was not. Athanasius claimed that Jesus was there in the beginning alongside God, begotten of the same substance. He was also a great admirer of Anthony the Great, and his approach to monasticism. For his many theological contributions, Athanasius is considered a key figure of Alexandrian theology and a father of Eastern Orthodoxy.

4th century- The Arian Controversary

Ephrem the Syrian

Theological Legacy: Pioneer of Christian Hymnography
Dates: 306-370
Location: Nisibis (modern Nusaybin, Turkey)
Position: Deacon, theologian, poet of the early Syriac Church
Influenced by: Syriac Christian tradition, Bishop Jacob of Nisibis
Key Concepts:

Defense of Nicene Orthodoxy
Christology (true divinity and humanity of Christ)
Use of poetry and hymns in theology
Symbolism and typology in scripture
Virgin Mary's role in the Incarnation
Heaven and the Christian life
Fighting heresy thru worship and hymns

Major Works:

Hymns on Paradise
Hymns on the Nativity
Hymns Against Heresies
Commentary on Genesis
Commentary on the Diatessaron
Hymns of Faith
Songs of Nisibis

Influenced: Syriac Christianity, Byzantine hymnography
Major Opponents: Arians, Marcionites, Bardaisanites, Manichaens
Titles/Honors: Saint, Doctor of the Church
Canonized: Yes. Pre congregation saint
Summary: He is considered one of the greatest theological poets of the fourth century and the father of Syriac Christianity. He made great theological contributions thru his role as deacon and teacher, using poetry, hymns, and symbolic artwork to express his point of view. Ephrem's hymns were very effective in defending Orthodoxy, biblical interpretation, and theological concepts of Christology, Mariology, and eschatology. He also used his musical hymns to combat Arianism and other heretical movements. Ephrem is honored as a doctor of the church, often referred to as "The Pillar of the Church" and the "Harp of the Holy Spirit".

Hilary of Poitiers

Theological Legacy: Hammer of the Arians
Dates: 310-368
Location: Poiters, Gaul (modern day France)
Position: Bishop of Poitiers
Influenced by: Athanasius of Alexandria, Origen
Key Concepts:

Defense of Trinity, Opposition to Arianism
Full divinity of Christ
Unity of the Father and the Son
Biblical exegesis
Integration of Eastern and Western churches
Salvation thru Christ

Major Works:

On the Trinity
On the Councils
Commentary on Matthew
Against Constantius
Commentary on the Psalms

Influenced: Ambrose of Milan, Augustine of Hippo
Major Opponents: Arians, Semi-Arians, Emperor Constantius II
Titles/Honors: Saint, Doctor of the Church
Canonized: Yes. Pre-Congregation Saint
Summary: He is regarded as one of the great early church theologians, who fought fiercely against the movement of Arianism. He emphasized the divinity and unity of Christ the Son with God the Father. He also worked to unite the growing differences between Eastern and Western Orthodoxy. Hilary was later exiled by Emperor Constantius II who was a stern supporter of Arianism. During this time he exile he produced many of his most famous works of theology, mostly centered on Triniatrian doctrine. For his apologetic defense of the Trinity he is often called the "Athanasius of the West" and the "Hammer of the Arians".

Apollinarus of Laodicea

Theological Legacy: Advocate of Christ's Divine Mind
Dates: 310-382
Location: Laodicia (modern Latakia, Syria)
Position: Bishop of Laodicea; Theologian
Influenced by: Athanasius of Alexandria, Apollinaris the Elder
Key Concepts:

Apollinarianism- Christ possessed a human body but his mind and spirt were the divine Logos
Emphasized the full deity of Christ and the unity of Christ's person (human and divine, where the divine takes precedence)
Was against Arianism

Major Works:

Apologies against Julian the Apostate and Porphyry
Anti-Arian and anti-heretical treatises
Influenced: The Apollinarian movement

Major Opponents: Gregory of Nazianzus, Gregory of Nyssa, Basil of Caesarea, Pope Damasus I
Titles/Honors: Founder of Apollinarianism
Canonized: No. Deemed a heretic
Summary: He was considered a controversial theologian who introduced the philosophy of Apollinarianism. This claimed Jesus was one person, with one governing mind that was divine. This was against the Constantinople and Chalcedonian Councils that claimed Christ was one person with two separate natures (human and divine). Apollinarus was not entirely against the church doctrine, and fought against Arianism and other forms of heresy. Despite being condemned as a heretic, Apollinarus still played a major role in shaping the classification of Christ's nature. This ideology could be seen as a precursor to Monophysitism that claimed Christ had only one nature that was united (divine and human).

Basil of Caesarea

Theological Legacy: Architect of Trinitarian terminology
Dates: 329-379
Location: Caesarea Mazaca, Cappadocia (modern day Turkey)
Position: Bishop of Caesarea, church father, theologian
Influenced by: Macrina the Younger, Gregory Thaumaturgus, Origen
Key Concepts:

Defense of the Nicene Trinitarian belief
Opposition to Arianism and Apollinarianism
Development of eastern monasticism
Care for the poor, social justice, and first hospital institutions
The divinity of the Holy Spirit
Communal monastic life

Major Works:

On the Holy Spirit
Against Eunomius
Longer Rules and Shorter Rules
Hexaemeron

Influenced: Gregory of Nyssa, Gregory of Nazianzus
Major Opponents: Arians and Neo-Arians, Eunomius, Apollinarians
Titles/Honors: Saint, Church Father, Doctor of the Church, Cappadocian Fathers, Three Holy Hierarchs
Canonized: Yes. Pre-congregation saint
Summary: He is regarded as St. Basil the Great for his many theological and institutional contributions to the church. He fervently defended the Nicene Trinitarian doctrine verse Arianism and Apollinarianism. He also promoted the full divinity and personhood of the Holy Spirit as the third person of the Holy Trinity against Pneumatomachians (Spirit-Fighters). He also implemented various new institutions to care for the sick and the poor, often considered the first public hospitals. St. Basil was a major architect of eastern monasticism with more emphasis on communal structure over isolation. He is often considered one of the fathers of Eastern Orthodoxy theology, known as the Cappadocian Fathers, alongside Gregory of Nyssa and Gregory of Naziansuz. He is given the highest honor as doctor of the church.

Gregory Nazianzus

Theological Legacy: Champion of the Trinity
Dates: 329-390
Location: Nazianzus, Cappadocia (modern day Turkey)
Position: Bishop of Sasima, Archbishop of Constantinople, Church Father
Influenced by: Basil of Caesarea, Athanasius of Alexandris, Gregory the Elder and Nonna (his parents)
Key Concepts:

Defense of the Nicene Trinity
Full divinity of the Holy Spirit
One divine essence with three distinct persons
Christ's full divinity and full humanity
Theosis (participation in God's life)
The mystery and worship of the Triune God

Major Works:

Five Theological Orations
Orations
Letters and Poems

Influenced: Eastern Orthodox theology, Council of Constantinople (381)
Major Opponents: Arians and Neo-Arians, Pneumatomachians, Apollinarianism
Titles/Honors: Saint, Church Father, Three Holy Hierarchs, Cappadocian Fathers
Canonized: Yes. Pre congregation
Summary: He is one of the greatest theologians of eastern Orthodoxy and one of the three Cappadocian fathers alongside Basil the Great and Gregory of Nysa. He was a champion of the Trinitarian belief, and further promoted the inclusion and equality of the Holy Spirit to the Father and the Son. This went against the Arianism and pneumatomachians movements. His concept of the Holy Spirit influenced the Council of Constantinople in 381 which completed the full trinity dogma as The Father, the Son, and the Holy Spirit. For his great contributions to Trinitarian theology he is honored as a doctor of the church and often referred to simply as "The Theologian".

Gregory of Nyssa

Theological Legacy: Advocate of Divine Infinity
Dates: 335-395
Location: Nyssa in Cappadocia (Asia Minor modern day Turkey)
Position: Bishop of Nyssa, Church Father, theologian
Influenced by: Basil of Caesarea (his older brother), Macrina the Younger, Gregory of Nazianzus, Origen
Key Concepts:

Defense of the Nicene Trinitarian doctrine
Distinction between one divine essence and three persons
Acceptance of the infinity and incomprehensibility of God
Spiritual growth as endless journey toward God (epektasis)
The image of God in humanity
Mystical theology and contemplation
Human transformation and participation in God

Major Works:

The Life of Moses
On the Soul and the Resurrection
Against Eunomius
The Great Catechism
On the Maknig of Man
On Not Three Gods

Influenced: Maximus the Confessor, Byzantine mysticism, Eastern Orthodox theolgoy
Major Opponents: Euonomius and Neo-Arianism, Arianism
Titles/Honors: Saint, Church Father, Cappadocian Fathers,
Canonized: Yes. Pre congregation.
Summary: He was the younger brother of St. Basil the Great, and one of the influential Cappadocian Fathers of the Eastern Orthodoxy. His greatest theological contributions came in defending the Nicene trinity against Arianism. He also helped define the paradox of the Trinity where God is one essence with three different personhoods. He developed the concept of spiritual transformation (known as epektasis) as an endless journey to get closer to God. One of my favorite of his concepts was the idea of God's incomprehensibility (which accepts that we can never truly understand the full of nature of God). Despite his high reverence in the Eastern Orthodoxy, he is not an official doctor of the church like the other two Cappadocian Fathers.

Ambrose of Milan

Theological Legacy: Advocate of Church Authority
Dates: 339-397
Location: Trier, Germany; Milan, Italy
Position: Bishop of Milan, theologian
Influenced by: Origen, Basil the Great, Athanasius
Key Concepts:

Defense of Nicene orthodoxy
The church's moral authority over imperial rulers
Allegorical interpretation of scripture
Christian ethics and pastoral leadership
Promoted Marian theology
Development of Western hymns and liturgy (Ambrosian Rite)

Major Works:

On the Duties of the Clergy
Six Days of Creation
On the Faith
On the Holy Spirit
Commentary on the Gospel of Luke
On the Death of Theodosius

Influenced: Augustine of Hippo
Major Opponents: Arianism, Empress Justina, Theodosius, Pagan factions
Titles/Honors: Saint, Doctor of the Church, Four Great Latin Fathers
Canonized: Yes. Pre-congregation
Summary: He is considered one of the four great Latin Fathers of the Church alongside Augustine of Hippo, Jerome, and Pope Gregory the Great. He migrated from Trier, Germany to Milan, Italy to become the leading theologian of Nicene Christianity. He established strict principles of church moral authority, ethics, and leadership. He also promoted the importance of Mary, as well as new forms of hymns and liturgy. As bishop he fought against Arianism and paganism, but also held emperors accountable (as an example that they were not above the Christian law). The most famous example includes Theodosius' massacre of citizens, which Ambose made the emperor do penance for his grave sin. Ambrose is also renown as the mentor of the great Augustine of Hippo whom he converted to the Christian faith.

Jerome of Stridon

Theological Legacy: Father of the Latin Bible
Dates: 342-420
Location: Rome, Antioch, Constantinople, and Bethlehem
Position: Priest, biblical scholar and theologian
Influenced by: Origen, Gregory of Nazianzus, Cicero, and Virgil
Key Concepts:

Return to original biblical languages (Hebrew vs Greek)
Promotion of Asceticism and Monasticism
The authority of Scripture
Hebrew Truth- Preference for the Hebrew Text of the Old Testament
Mary's role as perpetual virgin
Condemnation of many of Origen's concepts such as Pre-existence and Origen of Alexandria

Major Works:

The Vulgate (Latin translation of the Bible)
On Illustrious Men
Chronicle
Extensive letters and biblical commentaries
Influenced: Augustine, Western monasticism, biblical scholarship

Major Opponents: Helvidius (on Mary's virginity), Jovinian, Vigilantius, Pelagians, Rufinus of Aquileia
Titles/Honors: Saint, Doctor of the Church, Four Great Latin Fathers
Canonized: Yes. Pre congregation saint
Summary: He is considered one of the Four Great Latin Fathers that helped shape early Western Christianity. His greatest contributions came in the fields of biblical interpretation, asceticism, Mariology, and condemnation of Origenism. He spent the majority of his life studying scripture and practicing asceticism in Bethlehem. He helped translate the bible into Latin and was a strong supporter of the Old Testament in it's original form of Hebrew (vs Greek or Latin). Quite interestingly he changed sides on his views of Origen and became the lead instigator of the Origenist Controversy. He was also an early advocate for the perpetual virginity of Mary which later become official dogma at the Second Council of Constantinople (553). Jerome's Latin translation of the Bible became the standard text for over a thousand years, for this reason he is considered one of the great doctors of the church.

Evagrius Ponticus

Theological Legacy: Architect of the Eight Evil Thoughts
Dates: 345-399
Location: Ibora, Pontus (modern day Turkey); Jerusalem, Nitria, Scetis (Egypt)
Position: Desert Father, theologian, monk
Influenced by: Basil the Great, Gregory of Nazianzus, Macarius of Egypt, Anthony the Great, Didymus the Blind, and Origen
Key Concepts:

The eight evil thoughts (which later developed into the Seven Deadly Sins)
Ascetic discipline and spiritual warfare
The importance of prayer and meditation
The stages of the spiritual life (ascetic practice, contemplation of creation, and knowledge of God)
Discipline over temptation, passion, and demonic influences

Major Works:

The Parkitkos
Gnostic Chapters
On Pray/Chapters on Prayer)
On the Eight Evil Thoughts)

Influenced: John Cassian, Palladius of Galatia, Babai the Great, Isaac the Syrian, John Climacus, Maximus the Confessor
Major Opponents: Anti-Origenism, Some of his views were later condemned as Origenism
Titles/Honors: Desert Father, Evagrius the Solitary
Canonized: Partially. Venerated as Saint in Syriac Orthodox and Armenian Church but not Catholic or the Eastern Orthodox Church
Summary: He is considered one of the most influential theologians of the Desert Father movement, with an emphasis on asceticism/monasticism. While spending a majority of his life in isolation in the desert, Evagrius developed a structured approach to spiritual purification. He explained the dangers of temptation and demonic influence which required great discipline and prayer to overcome. He introduced the concept that every human is tortured by a common set of eight evil thoughts; gluttony, lust, avarice, sadness, anger, acedia, vainglory, and pride. John Cassian and Pope Gregory later transmitted this theory into seven deadly sins (merging Sadness/Acedia into Sloth, Vainglory merged with Pride, and introducing the sin of Envy). Despite Evagrius' great theological contributions to spiritual discipline, many of his concepts were aligned with Origenism which was deemed heretical.

John Chrysostom

Theological Legacy: Doctor of Priesthood theology
Dates: 347-407
Location: Antioch, Syria
Position: Archbishop of Constantinople, Church father
Influenced by: Meletius of Antioch, Diodore of Tarsus
Key Concepts:

Moral teaching based on scriptures
Care for the poor and criticism of the wealthy
Church reform and clerical discipline
The important role of the Eucharist
Asceticism and holiness in everyday life
Favored literal interpretation vs allegorical

Major Works:

On the Priesthood
Homilies on Matthew
Homilies on John
Homilies on Acts
Homilies on the Pauline Epistles
On the Statues

Influenced: Byzantine and Eastern Orthodox theology
Major Opponents: Empress Eudoxia, Theophilius of Alexandria
Titles/Honors: Saint, Three Holy Hierarchs, Doctor of the Church, Four Great Greek Fathers, Chrysostom (Golden-Mouthed).
Canonized: Yes. Pre congregation
Summary: He is regarded as one of the greatest preachers in early Christianity and a very influential theologian from the Eastern orthodoxy. For this reason he has the title of Chrysostom, which means golden-mouthed. He is one of the Three Holy Hierarchs alongside Basil the Great and Gregory of Nazianzus. He is considered the founder of the Divine Liturgy which is still in use today by most Eastern Christian churches. Perhaps his greatest contribution to the church was his reform of church structure and clerical discipline. He strongly advocated for the poor and denounced those who lived in excessive wealth, luxury, and corruption. One of his most famous targets was Empress Eudoxia and other high ranking bishops which eventually led to his exile. His role in shaping the church, liturgy, charitable efforts, and theology makes him one of the great doctors of the church and one of the Four Great Greek Fathers of the Church (alongside Athanasius of Alexandria, Basil the Great, Gregory of Nazianzus).

Pelagius

Theological Legacy: Champion of Free Will
Dates: 354-418
Location: Britain, Rome, North Africa, and Palestine
Position: Christian monk, theologian
Influenced by: Christian ascetic
Key Concepts:

Free will
Human moral responsibility
Rejection of inherited original sin
Ability of humans to choose obedience to God
Emphasis on moral effort and holy living

Major Works:

On Free Will
On Nature
Commentary on Romans
Letter to Demetrias

Influenced: Pelagianism
Major Opponents: Augustine of Hippo, Jerome, Pope Innocent I, Pope Zosmus
Canonized: No. Condemned a heretic
Summary: He is considered the champion of free will, emphasizing that humans freely choose between right and wrong. He also rejected the concept of original sin, and claimed that humanity was born innocent and free of sin (which became a controversial stance). This later went against Augustine's teachings that humans had inherited original sin and needed grace from God to achieve salvation. His teachings became known as Pelagianism and became a contested topic during the 4th and 5th century. Although he was ultimately deemed a heretic at the Synod of Diospolis for rejecting original sin, his concepts helped refine the theological definition by creating a balance between free will and divine grace.

Augustine of Hippo

Theological Legacy: Champion of Divine Grace
Dates: 354-430
Location: Thagast, Numidia (modern Algeria); Carthage, Rome, Milan, and Hippo (modern Annaba, Algeria)
Position: Bishop of Hippo
Influenced by: Ambrose, St. Paul, Neoplatonism, Cicero
Key Concepts:

Original Sin
Divine grace and salvation
Free will and predestination
The Trinity
Just War theory
The problem of evil
The City of God vs the City of Man
Divine illumination and Christian epistemology

Major Works:

Confessions
City of God
On the Trinity
On Christian Doctrine
Against the Manicheans
Enchiridion

Influenced: Martin Luther, John Calvin, Thomas Aquinas, Western theology and philosophy
Major Opponents: Manichaens, Donatists, Pelagians
Titles/Honors: Saint, Doctor of the Church, Four Great Latin Fathers of the Church
Canonized: Yes. Pre congregation
Summary: He is considered the greatest of all Christian theologians alongside Thomas Aquinas. He is regarded as one of the foundational Four Latin Fathers of the Church that helped shape Western theology and philosophy. At an early age he was renown for his philosophical studies and began as a Manichean (who believed in Dualism). However he was later converted by his mother Monica as well as the teachings of Ambrose. He was able to make sense of the Christian beliefs thru Philosophical ideals, that rejected Dualisms, and found an answer to the problem of evil (which he deemed was the lack there-of God). He also introduced many new philosophical concepts to Christian theology such as the importance of grace, original sin, free will, predestination, just war theory, and the problem of evil. He later became bishop of Hippo where in his final years he wrote the City of God to emphasize the humanity lived in an earthly city, however the City of God was a spiritual realm that could only be achieved thru faith and salvation. Many of his concepts went on to influence the great theologians of the Middle Ages such as Martin Luther, John Calvin, and Thomas Aquinas.

John Cassian

Theological Legacy: Father of Western Monasticism
Dates: 360-435
Position: Monk, writer, theologian
Influenced by: Desert Fathers, Evagrius Ponticus, John Chrysostom
Key Concepts:

Monastic discipline and communal life
Asceticism and spiritual purification
Eight principle vices/evil thoughts
Discernment of thoughts
Prayer and contemplation
Purity of the heart
Human free will and cooperation with divine grace
Spiritual formation and the interior life

Major Works:

Institues of the Coenobia- monastic practices and the eight principle vices
Conferences- Conversations with Egyptian monks
On the Incarnation o the Lord against Nestorius- critique of Nestorianism

Influneced: Benedict of Nursia, Western monasticism
Major Opponents: Nestorius, Pelagianism
Titles/Honors: Saint
Canonized: Yes. Pre-congregation
Summary: Influenced by the Desert Fathers and the example of Anthony the Great, he is considered the father of Western Monasticism. He is considered one of the foremost transmitters and writers of all aspects of asceticism and spiritual discipline. He spent years living in the deserts of Egypt focusing on deep prayer, spiritual discipline, and the battle against temptation. He expanded on Evagrius' concept of the eight evil thoughts by turning them into eight vices (gluttony, lust, greed, anger, sadness, acedia, vainglory, and pride). Which Pope Gregory the Great later refined into 7 deadly sins. Cassian's writings on fighting temptation and the monastic lifestyle later inspired the great Benedict of Nursia.

Eutyches of Constantinople

Theological Legacy: Father of Monopysitism
Dates: 375-454
Location: Constantinople
Position: Presbyter, monk, archimandrite
Influenced by: Cyril of Alexandria
Key Concepts:

Rival of Nestorianism
Taught that Christ was two natures before the Incarnation then become one nature on earth (Monophysitism)
Christ's divine nature ultimately swallows up his human nature

Influenced: Council of Chalcedon (451)
Major Opponents: Flavian of Constantinople, Eusebius of Dorylaeum, Pope Leo the Great
Titles/Honors: Revered as a leader of the Anti-Chalcedonian movement
Canonized: No. Condemned a heretic.
Summary: He was one of Nestorius' greatest rival, as a stern defender of Christ's one personhood with one nature (known as Monophysitism). This concept was also however later rejected by the Council of Chalcedon since it felt his divine nature would dominate his human nature. Ultimately the Orthodox church accepted the Hypostatic Union which accepted that Christ was one person, with two distinct natures (human and divine). Eutyches' concepts were later condemned as heresy that influenced one of the most significant ecumenical councils at Chalcedon. His concept of Monophysitism was also rejected by the anti-Chalcedonian faction that disagreed Christ had two natures, and also disagreed that Christ's divine nature dominated his human nature. Instead they believed that Christ had one nature that was united. It was ultimately a difference over proper terminology that lead to the Chalcedonian Schism which established the Oriental Orthodox Church.

Cyril of Alexandria

Theological Legacy: Champion of the Theotokos
Dates: 376-444
Location: Alexandria, Egypt
Position: Patriarch of Alexandria, theologian church father
Influenced by: Athanasius of Alexandria, Theophilus of Alexandria (his uncle)
Key Concepts:

Hypostatic Union (union of divine and human nature of Christ)
Christ is one person, not two persons acting together
Defense of Mary as Theotokos (God-bearer)
The incarnation of the Word
Christ has one nature is fully divine and fully human (Miaphystism)

Major Works:

Second Letter to Nestorius
Third Letter to Nestorius
Twelve Anathemas Against Nestorius
Commenaty on John
Commentary on Luke
Against Julian

Influenced: Council of Ephesus (431), Eastern Orthodox theology, Oriental Orthodox theology
Major Opponents: Nestorius (Patriarch of Constantinople)
Titles/Honors: Saint, Doctor of the Church, Pillar of the Faith, Seal of All the Fathers
Canonized: Yes. Pre-Congregation
Summary: He is considered the champion of the Christology debate, who emphasized Christ's one united personhood as divine and human. He fought tirelessly against Nestorius the Patriarch of Constantinople who claimed Christ was two persons. Cyril also promoted the concept of Mary's role as mother of God (which was also rejected by many factions). He is considered one of the key figures that led to the Council of Ephesus which later caused one of the first major schisms in the church. Even though Nestorius himself did not lead the schism, it is referred to as the Nestorian Schism which later established the Church of the East. Cyril is considered one of the Eastern father's that helped establish Christ's nature as one person with two natures that was finalized at the Council of Chalcedon (451).

Peter Chrysologus

Theological Legacy: Advocate of Incarnation of God
Dates: 380-450
Location: Ravenna, Italy
Position: Bishop of Ravenna, preacher, theologian
Influenced by: Bishop Cornelius of Imola, Nicene tradition
Key Concepts:

The Incarnation of Christ
Orthodox Christianity
The Apostle's Creed
Repentance and Christian moral living
Frequent reception of the Eucharist
Pastoral preaching that was clear, concise, and accessible

Major Works:

176 surviving homilies

Influenced: Western theology on Christology
Major Opponents: Arianism, Monophysitism
Titles/Honors: Saint, Doctor of the Church, Doctor of Homilies
Canonized: Yes. Pre-congregation
Summary: He was a bishop from Ravenna, which was the brief capital of the Roman Empire after the fall of Rome. He was renown as one of the greatest preachers to have ever lived which is why he is often referred to as the Doctor of Homilies. He lived thru the peak of the Trinity and Christology debates, fervently defending the Orthodox stance of the Nicene Council. He was especially an advocate of the Incarnation of God, the unity of Christ's divine and human nature, and Mary as the Theotokos. Although he did not participate in the Council of Ephesus or Chalcedon, he stood in support of the Christian Orthodox rulings. 176 of his sermons are still preserved in written form, which demonstrate his passion for the Apostles Creed, repentance, moral living, and the importance of the Eucharist. For his passionate sermons and Orthodox concepts, he is considered a doctor of the church.

Nestorius of Constantinople

Theological Legacy: Advocate of the Two-Person Christ
Dates: 386-451
Location: Syria, Constantinople
Position: Patriarch of Constantinople
Influenced by: Theodore of Mopuestia, Diodore of Tarsus
Key Concepts:

Strong distinction between Christ's human form and Christ's divine form
Defender of Christ's genuine humanity (separate from his divinity)
Promoted Christokos (Mother of Christ) over Theotokos (Mother of God)
Promoted Christ as two persons with two natures
Opposition to Monophysitism (one person, one nature)
Opposition to the Hypostatic Union (One person, two natures)

Major Works:

The Bazaar of Heracleides

Influenced: Council of Ephesus (431), Council of Chalcedon (451), Church of the East
Major Opponents: Cyril of Alexandria, Pope Celestine I
Titles/Honors: Father of Church of the East
Canonized: No. However he is venerated as "Mar" in the Church of the East
Summary: He is considered a controversial theologian who was the main subject of the Council of Ephesus (431) and Council of Chalcedon (451). His teachings that Christ was two persons, were condemned by the Orthodox church who claimed Christ was one person with two natures. Nestorius also favored Mary's role as the mother of Christ (the Christokos) over the Theotokos (mother of God). The Church ultimately felt that if they were to truly defend the trinity, than the only logical explanation was that Mary must be the mother of God. Nestorius came into direct conflict with Cyril of Alexandria, which caused tension between the Antiochene and Alexandrian theological schools. The ruling in favor of the Hypostatic Union and the Theotokos ultimately led to the Nestorian schism (which Nestorian himself was not a part of). Despite being considered a heretic by the Catholic Church he is celebrated as the father of Eastern Syriac Christianity and the Christian Church of the East.

Dioscorus of Alexandria

Theological Legacy: Champion of Miaphysitism
Dates: 390-454
Location: Alexandria, Egypt
Position: Pope and Patriarch of Alexandria
Influenced by: Cyril of Alexandria
Key Concepts:

Miaphysitism- Christ is one person with one equal nature, where his divine nature does not diminish his human nature (unlike Monophysitism)
Defense of the Cyril's teachings of the Hypostatic Union
Fought against Nestorius' teachings of Christ as two persons with two natures

Influenced: Coptic Orthodox Church, Oriental Orthodox Church
Major Opponents: Nestorius, Flavian of Constantinople, Pope Leo the Great, Eutches
Titles/Honors: "Great" in Oriential Orthodox Tradition
Canonized: Partially. Recognized as a saint in Oriental Orthodox tradition
Summary: He was the successor of Cyril of Alexandria who defended the concept of Miaphysitism. He fought against Nestorianism as well as Eutyches' concept of Monophysitism and Pope Leo the Great's concept of Dyophysitism. This was a unique time in the Christology debates where three views on Christ's theory were at war with one another. Dioscorus managed to highjack the debate when he oversaw the Second Council of Ephesus (449), later referred to as the "Robber Synod". This decision was later rejected by the western church and deemed as heresy. After the Council of Chalcedon ruled in favor of the Diophysitism (one person, two natures), Dioscorus became the key figure in leading the Anti-Chalcedonian movement. This movement was one of the big 3 eastern schisms that established the Oriential Orthodox Church which still exists today. Although Dioscorus is regarded as "Great" in Oriental Orthodox tradition, he is seen as somewhat of a robber and villain in Western tradition for his role in the murder of Flavian ( a lead figure of the Chalcedonian Dyophisite concept).

5th century - Christology: The Personhood of Christ

Pope Leo the Great

Theological Legacy: Champion of Dyophysitism
Dates: 400- 461
Location: Rome, Roman Empire
Position: Bishop of Rome
Influenced by: Athanasius of Alexandria, Augustine of Hippo
Key Concepts:

Champion of Dyophysitism- One person with two natures
Strong defense of the unity of Christ's personhood (divine and human)
Emphasized the importance of the Petrine office (the papacy)

Major Works:

Tome of Leo
Numerous Letters and sermons

Influenced: Council of Chalcedon
Major Opponents: Eutyches (Monophysitism)
Titles/Honors: Saint, Doctor of the Church, "Great"
Canonized: Yes. Pre congregation
Summary: He played the leading role at the Council of Chalcedon pertaining to the Christology debates. With his Tome of Leo, he strongly opposed Eutyche's Monophysite teachings (one person with one nature) in favor of the concept of the Dyophysitism (one person with two natures). This became the accepted doctrine that is still in place today, that accepts Christ as one person with two distinct natures, divine and human (without confusion, change, division, or separation). This debate over the nature of Christ led to the Anti-Chalcedonian movement which supported the concept of Miaphysitism (one nature, where the divine form does not dominate, but it equal to the human form). What even furthered the anti-Chalcedonian divide, was when Pope Leo began emphasizing the supreme authority of the Bishop of Rome. While the Bishop of Rome has always been considered the pope (since Saint Peter), Pope Leo is seen as the first to fully exercise his papal authority over all church patriarchies (Alexandria, Antioch and Constantinople). He also played a major political role in deterring Attila the Hun from conquering Rome in 452.

Severus of Antioch

Theological Legacy: Advocate of Miaphysitism
Dates: 465-538
Location: Antioch, Constantinople, Palestine, and Egypt
Position: Patriarch of Antioch
Influenced by: Cyril of Alexandria, Dioscorus of ALexandria
Key Concepts:

Miaphysitism
Rejection of Nestorianism, Monophysitism, and Dyophysitism

Major Works:

Cathedral Homilies
Select Letters
Against the Impious Grammarian

Influenced: Syriac Orthodox Church, Coptic Orhodox Church, Armenian Apostolic Church
Major Opponents: Chalcedonianist
Titles/Honors: Leader of the anti-Chalcedonianian movement
Canonized: Partially- Honored as saint in Oriental Orthodox Churches
Summary: After the divisive Council of Chalcedon, Severus of Antioch succeeded Dioscorus as the leading figure of the Anti-Chalcedonian movement. This movement firmly supported the Miaphysite ideal, that Christ was one person with one unified nature (that was equally divine and human). While Cyril is considered the founder of Miaphysitism, and Dioscorus was the schismatic, Severus can be seen as the architect of the newly established Oriental Orthodox Church. Although the debate on the nature of Christ went on for many years after, Severus solidified the Anti-Chalcedonian movement with his theological writings that helped shape the Oriental Orthodox Church.

Isaac of Antioch

Theological Legacy: Defender of Miaphysitism
Dates: 408-450
Location: Antioch, Syria
Position: Priest, writer, theologian
Influenced by: Ephrem the Syrian
Key Concepts:

Repentance and moral reform
Asceticism and monastic discipline and structure
Calls to Christian virtue
Defense of Orthodox Christology (one person with two natures)

Major Works:

Hundreds of Syriac memre (metrical homilies)

Influenced: Syriac tradition, literature, hymnography
Titles/Honors: "Doctor of the Syrians"
Canonized: No
Summary: He is considered one of the most important theological writers of Syriac Christianity, renowned for his preaching, poetry, hymns, and theological works. He was influenced by the great poet Ephrem the Syrian, and established a new style of metrical homilies. He famously promoted repentance, monasticism, ethics, and morals. He also addressed ongoing controversies (such as the Parrot and the Trisagion controversary). Although he didn't play a major role in administration or doctrine reform, his legacy lasts thru his poetic/theological works.

Boethius

Theological Legacy: Philosopher of Changing Fortune
Dates: 480-525
Location: Rome (Ostrogothic Kingdom)
Position: Roman senator, philosopher, theologian
Influenced by: Plato, Aristotle, Neoplatonism, Stoicism, Porphyry, Greco-Roman philosophy
Key Concepts:

Wheel of Fortune
Providence and fate
Free will and divine foreknowledge
Highest good (True happiness found in God)

Major Works:

The Consolation of Philosophy
De Trinitate
De Institutione Musica
Commentaries on Aristotle and Porphyry

Influenced: Thomas Aquinas, Dante Alighieri, Geoffrey Chaucer, King Alfred the Great, Scholasticism
Titles/Honors: Saint
Canonized: Yes. Pre congregation
Summary: He was a Roman senator and magister officiorum (chief administrator) well versed in Greek and Roman philosophy. As a statesman he brought a unique perspective on Christian theology, bridging the gap between philosophy, society, and Christianity. He is most famous for his Wheel of Fortune concept, which explains that wealth, fortune, and status are not permanent means of happiness. The only true happiness that can be achieved is from the highest eternal good, which is found in God. Many of his writings on philosophy and theology are considered an early form of scholasticism that influenced key writers and theologians during the Middle Ages.

6th Century (Christology: The Nature of Christ)

Pseudo-Dionysius the Areopagite

Theological Legacy: Champion of the Incomprehensibility of God
Dates: 475-525
Location: Syria, Byzantine Empire
Position: Theologian, Philosopher
Influenced by: Neoplatonism, Greek Church Fathers
Key Concepts:

Apophatic Theology- God transcends all human concepts
Mystical Union with God- the soul ascends toward God
God and the church are in union with one another thru the apostolic succession
Creation is an example of God's goodness
Integration of Greek philosophy with Christian theology

Major Works:

The Divine Names
Mystical Theology
The Celestial Hierarchy
The Ecclesiastical Hierarchy
Letters

Influenced: Maximus the Confessor, John Scotus Eriugena, John of Damascus, Gregory Palamas, Hugh of St. Victor, Bonaventure, Thomas Aquinas, Meister Eckhart, Gregory of Narek Canonized: No
Summary: He is regarded as one of the great early Christian theologians, however his identity was unknown and he wrote with an anonymous pseudonym his entire life. His pseudonym is a reference to the biblical figure of Dionysius the Areopagite who was an Athenian judge that was converted by the apostle Paul. Pseudo-Dionysius was greatly inspired by Greek philosophy and the Greek church fathers, thus the association to this Greek convert. He essentially integrated Greek philosophy of Neoplatonism with Christian theology. His most famous concept was Apophatic Theology which stressed the incomprehensibility of God. This is also referred to as negative theology, which only explains what God is not rather then trying to theorize what God is. He also promoted the practice of mysticism and the souls journey to God. Although his identity was never truly known his theological writings went on to inspire some of the greatest Christian theologians in both Eastern and Western Orthodox.

Pope Gregory the Great

Theological Legacy: Architect of the Seven Deadly Sins
Dates: 540-604
Location: Rome, Roman Empire
Position: Pope, Doctor of the Church, theologian
Influenced by: Augustine of Hippo, Benedict of Nursia, Ambrose of Milan
Key Concepts:

Pastoral leadership, care of souls
Humility in church leadership
Monastic spirituality
Missionary evangelism
The moral and allegorical interpretation of Scripture
Purgatory
Prayers for the dead

Major Works:

Pastoral Rule
Moralia in Job
Homilies on Ezekiel
Homilies on the Gospels
Dialogues

Influenced: Medieval papacy, western monasticism
Major Opponents: Donatists
Titles/Honors: Saint, Doctor of the Church, "Great", Four Great Latin Fathers
Canonized: Yes. Pre-congregation
Summary: He is regarded as one of the most influential popes and the final member of the Mount Rushmore of Great Latin Church Fathers alongside Ambrose, Jerome, and Augustine of Hippo. Following the lead from Pope Leo, Gregory furthered the authority of the Roman church as the administrative heart of the church (as well as many state matters). He was an advocate of monasticism, charity, and evangelization. He fine tuned the eight vices into seven deadly sins, by merging sadness into envy, acedia into sloth, and vainglory into pride (Pride, Envy, Wrath, Sloth, Greed, Gluttony, and Lust). Pope Gregory famously appointed Augustine of Canterbury to evangelize Anglo-Saxon England. This marked the beginning of the Western Church's missionary work during the Middle Ages. He also provided great theological insight on the role of pastors, spirituality, biblical interpretation, and the concept of Purgatory. While this concept had already been in place, Gregory played an influential role in defining Purgatory as a state of purification that required prayers from the living.

Isidore of Seville

Theological Legacy: Compiler of Christian Knowledge
Dates: 560-636
Location: Seville, Visigoth Kingdom (modern Spain)
Position: Archbishop of Seville
Influenced by: Augustine of Hippo, Ambrose, Jerome, Pope Gregory the Great
Key Concepts:

Preservation of classical learning
Unity of church and society
Christian education
Biblical interpretation
Integration of Greco-Roman philosophy with Christian theology

Major Works:

Etymologiae (Origins)- Encyclopedia of knowledge
On the Nature of Things
History of the Goths, Vandals, and Suebi
Sentences
On Ecclesiastical Offices

Influenced: Medieval education, Alcuin
Major Opponents: Arianism,
Titles/Honors: Saint, Doctor of the Church
Canonized: Yes. Pre-congregation saint
Summary: He was an influential archbishop from Seville (under the Visigoth Kingdom) who strengthened the church in Spain during the early Middle Ages. He was a historian and archivist who felt that knowledge and philosophy of the ancient world could benefit and advance the Christian world. His encyclopedia Origins became one of the most popular scholarly books during the Middle Ages. He was especially against Arianism, which still held a prominent place among Visigoth leadership. He was a central figure in the early development of education for the clergy as well as the laity for which he is honored as a doctor of the church.

7th Century- Christology: The Will of Christ

Maximus the Confessor

Theological Legacy: Champion of Dyothelitism
Dates: 580-662
Location: Constantinople, North Africa, Rome
Position: Monk, theologian
Influenced by: Gregory of Nazianzus, Gregory of Nyssa, Evagrius Ponticus
Key Concepts:

Dyothelitism (Christ possesses two wills; divine and human)
Theosis (being in union with God)
Cosmic redemption and participation in God
Harmony of human and divine wills
The logoi of creation existing in the divine Logos

Major Works:

Ambigua to John
Questions to Thalassius
Mystagogy
On the Cosmic Mystery of Jesus Christ

Influenced: John of Damascus, Eastern Orthodox theology
Major Opponents: Monothelites, Patriarch Purrhus of Constantinople, Emperor Constans II
Titles/Honors: Saint, "The Confessor"
Canonized: Yes. Pre congregation saint
Summary: Maximus the Confessor is best known for promoting the concept of Christ's two separate wills within his two natures of divine and human. He defended this doctrine against Monothelitism (two natures, but one will). This essentially added another layer to the Christology debate pertaining not to his personhood or his nature, but his will. Maximus was eventually arrested and exiled for his teachings on Dyothelitism, during which his tongue and right hand were severed. His teachings, however, were later vindicated and accepted as orthodox by the church. Maximus is considered the champion of Dyothelitism (two natures with two wills) which has become official doctrine to this day. He also emphasized the vital role of spirituality, cosmology, and humanity's need to find union with God (Theosis).

Isaac of Nineveh

Theological Legacy: Mystic of Spiritual Purification
Dates: 613-700
Location: Beth Qatraye (modern day Qatar)
Position: Monk, theologian, bishop of Nineveh
Influenced by: Evagrius Ponticus, the Desert Fathers
Key Concepts:

Divine mercy and universal love
Compassion toward all creation
Meditation and contemplation
Purification of the heart
Asceticism as the path to Theosis
God's judgement and mercy
The foundational role of humility and spirituality

Major Works:

Ascetical Homilies
Various mystical and spiritual treatises

Influenced: Eastern Orthodox spirituality, Hesychasm, and Byzantine monasticism, Symeon the New Theologian, Gregory Palamas
Titles/Honors: Saint
Canonized: Yes. Pre-congregation saint
Summary: He is regarded as one of the greatest mystical writers of Eastern Christianity. He was bishop of Nineveh for a brief period before he decided to pursue an ascetic lifestyle, inspired by the Desert Fathers. It was during this time he explored themes of meditation, spirituality, and deep prayer. He used this experience to write his famous Ascetical Homilies which explains his theology of repentance, humility, inner peace, and love for all. He emphasized that true grace and salvation comes thru love of all creatures; friends, family, animals, and even one's enemies.

8th Century- The Iconoclastic Controversary

Bede the Venerable

Theological Legacy: Historian of the English Church
Dates: 672-735
Location: Northumbria (modern day England)
Position: Monk, Priest, Theologian, scholar
Influenced by: Augustine, Gregory the Great, Jerome, Ambrose, Isidore of Seville, Origen
Key Concepts:

Preservation of church history
Biblical interpretation (exegesis)
Christian education and scholarship
Computus (date of Easter)
Popularization of AD calendar system

Major Works:

Ecclesiastical History of the English People
On the Reckoning of Time

Influenced: Medieval historians
Titles/Honors: Saint, Doctor of the Church, "The Venerable Bede", "Father of English History"
Canonized: Yes. Pre-Congregation
Summary: He was an Anglo-Saxon priest and considered one of the most important scholars and historians of the Middle Ages. He spent the majority of his life in monasteries studying scripture and historical archives. His masterpiece, History of the English People, became one of the most popular writings of English and church history during the Middle Ages. He also promoted education and scholarship of Christianity as well as a focus on the Christian calendar system. This was based on the historical chronological events as well as lunar cycles to help determine the date of Easter as well as other liturgical seasons. He also popularized the calendar system of BC/AD (Before Christ/Anno Domini) which was Latin for "Year of Our Lord".

John of Damascus

Theological Legacy: Defender of Icons
Dates: 675-749
Location: Damascus, Syria (Umayyad Caliphate)
Position: Monk, priest, theologian, apologist
Influenced by: Early Church Fathers, Greek philosophy
Key Concepts:

Defense of icons
Orthodox Christian doctrine
Trinity and Christology
Veneration vs worship
Mariology: Role of Mary
Systematic theology

Major Works:

The Fountain of Knowledge
Three Treatises on the Divine Images

Influenced: Second Council of Nicaea (787)
Major Opponents: Byzantine Iconoclasts, Emperor Leo III
Titles/Honors: Saint, Doctor of the Church, "Golden Speaker", Last of the Greek Fathers, Doctor of the Assumption
Canonized: Yes. Pre-congregation saint.
Summary: He was an influential Christian theologian and priest who lived in Syria under Muslim rule. His greatest claim to fame was his defense of icons during the Iconoclastic Controversary. The Iconoclast movement began in the Byzantine Empire, and quickly spread throughout the Christian world, strongly against the portrayal of God, Jesus, Mary, and the saints. However John of Damascus argued that since God revealed himself to mankind thru Jesus, therefore it should be allowed that we can visualize him thru art and images. This issue was officially settled at the Second Council of Nicaea where he became the champion apologist for religious icons. The key distinction in the practice of Icons, was that they could be venerated (honored) but were not to be worshiped like God. John of Damascus also advocated for the important role of Mother Mary which became highly influential in both Eastern and Western Orthodox.

Paschasius Radbertus

Theological Legacy: Architect of Transubstantiation
Dates: 785-865
Location: Picardy (modern day France)
Position: Benedictine monk, theologian, abbot
Influenced by: St. Augustine, Benedictine tradition
Key Concepts:

The Eucharist and the Real Prescence of Christ
Early development of the concept of Transubstantiation
Perpetual virginity of Mary
Monastic education and reform

Major Works:

On the Body and Blood of the Lord
On Faith, Hope, and Charity
On the Virgin Birth
Commentaries on Matthews, Psalms, and Lamentations
Biographies of Adalard and Wala of Corbie

Influenced: Eucharistic theology, Carolingian Renaissance, Fourth Lateran Council (1215)
Major Opponents: Ratramnus of Corbie, Rabanus Maurus
Titles/Honors: Saint
Canonized: Yes. Canonized in 1073 by Pope Gregory VII
Summary: He was a Benedictine monk who became one of the leading theologians of the Carolingian Renaissance which would soon become the Holy Roman Empire. He is best known as the early developer of the concept of Transubstantiation where Jesus is present in the Eucharist (not just symbolically). This concept sparked a new era of debates over the interpretation on the Eucharist. The question was whether Christ was truly present in the bread and wine. Paschasius was challenged by other prominent monks such as Ratramnus who felt it was more of a symbolic presence. This concept of Christ's real presence in the Eucharist evolved over the years and eventually became accepted as official church doctrine at the Fourth Lateran Council (1215)

9th Century- The Filiqoue Clause and Transubstantiation

Claudius of Turin

Theological Legacy: Leader of the Second Iconoclast Controversary
Dates: 8th century- 827
Location: Turin, Italy (Carolingian Empire)
Position: Bishop of Turin
Influenced by: Augustine, Jerome, Leidrad of Lyon
Key Concepts:

Iconoclasm (Against religious images)
Criticism of the cult of relics and pilgrimages
Emphasis on scripture and biblical exegesis
Equality of the apostles
Fallibility of church leaders and institutions

Major Works:

Book on Images
Commentaries on Biblical books
A Chronicle

Influenced: Protestant concepts (most notably the emphasis on scripture)
Major Opponents: Dungal, Jonas of Orleans
Canonized: No.
Summary: He was one of the lead theologians who favored iconoclasm, against the veneration of images, relics, and any form of devotional practice. This was considered a second wave after the first Byzantine wave was settled at the Second Council of Nicaea (787). Claudius however was from the Latin West, and publicly began preaching and removing images throughout his diocese. He also preached on the importance of scripture, as the source of all worship. Both of concepts were deemed controversial and heretical by the Orthodox church. His emphasis on the scripture as the only true authority is often seen as a precursor to the Protestant ideals of "Sola Scriptura". Despite his criticisms of the church Claudius was not deposed or exiled, yet remained bishop of Turin until his death.

Ratramnus of Corbie

Theological Legacy: Critic of Transubstantiation
Dates: 800-868
Location: Amiens, Frankish Kingdom (modern northern France)
Position: Benedictine monk, theologian
Influenced by: St. Augustine of Hippo, Paschasius Radbertus
Key Concepts:

Spiritual understanding of Christ's presence in the Eucharist
Defense of predestination
Support for the Filioque clause (which states the Holy Spirit proceeds from the Father and the Son)
Distinction between visible signs and spiritual presence in the sacraments

Major Works:

On the Body and Blood of the Lord
On Predestination
Against the Objections of the Greeks
On the Birth of the Christ
Letter on the Cynocephali- Rationality on Dog-headed people

Influenced: Eucharistic theology, Protestant reformers
Major Opponents: Paschasius Radbertus (on the Eucharist), Hincmar of Reims (on predestination), Easter Critics of the Filioque
Canonized: No.
Summary: He was a student of Paschasius Radbertus who challenged him on his concept of the actual presence of Christ in the Eucharist. Ratramnus' belief was that Christ was present in the Eucharist in a spiritual and symbolic matter, not so much a real physical presence. This concept of course was later rejected and Paschasius' teachings on the Transubstantiation became official church doctrine. Ratramnus also favored the Augustinian concept of predestination as well as the Filioque clause, which would become other contested topics by the Eastern Orthodox church. Although many of his teachings were rejected by the church he is still considered a very influential theologian of the Middle Ages.

Johannes Scotus Eriugena

Theological Legacy: Architect of Neoplatonism
Dates: 810-877
Location: Leon, Paris; West Francia (modern day France)
Position: Theologian, poet
Influenced by: St. Augustine, Gregory of Nyssa, Maximus the Confessor, Neoplatonism, Dionysius the Areopagite
Key Concepts:

Harmony of faith and reason
Exitus-redditus- Neoplatonic concept of procession from and return to God
The vital role of nature's connection to existence (Pantheism)
Theophany (creation as a manifestation of God)
Emphasis on dialectic and philosophical theology

Major Works:

Periphyseon- On the Division of Nature
On Predestination
Latin translations of Pseudo-Dionysius the Areopagite
Commentaries on Pseudo-Dionysius and Maximus the Confessor

Influenced: Nicholas of Cusa, Meister Eckhart, Christian mysticism, Scholastic theology
Major Opponents: Critical views of predestination
Canonized: No
Summary: He is often regarded as one of the greatest Western philosophers of the Carolingian Renaissance alongside Boethius and Anselm. He played a crucial role in translating Greek Christian texts to Latin, which became widespread throughout the Western Christian kingdoms. Drawing from Augustine and Neoplatonism he promoted the concept of predestination and developed his concept of Periphyseon, which described Natures role as interconnected with God (this was later deemed heretical as a form of Pantheism). He strived to unite theology with reason and also promoted the concept that all creation came from God, and all life would eventually return to God. Although many of his views were later rejected, he was still considered a very influential philosopher who furthered mysticism and scholastic theology.

Gottschalk of Orbais

Theological Legacy: Champion of Double Predestination
Dates: 803-868
Location: Saxony, Carolingian Empire (present day Germany)
Position: Benedictine monk, theologian
Influenced by: St. Augustine of Hippo
Key Concepts:

Double predestination (God has decided those meant for grace and those meant to be damned)
Sovereignty of divine grace
Limited scope of redemption to the elect
Strong Augustinian view of human sinfulness and dependence on God's grace

Major Works:

On Predestination
On the Triune Deity

Influenced: Critics of predestination
Major Opponents: Rabanus Marcus, Hincmar, John Scotus Eriugena
Canonized: No.
Summary: He was a firm Augustinian, best known as a strong advocate for the concept of double predestination. This essentially expanded on Augustine's concept that God had already chosen the people that were saved by grace, by adding the opposing extreme that God had chosen those who would be damned. This concept is also known as reprobation and became very controversial during the 9th century. Gottschalk claimed he was just following Augustine's philosophy with a more direct understanding. This theory (as well as predestination in general) became officially deemed heresy at the Synod of Mainz (848) and Synod of Quierzy (849). Nonetheless his theological concepts were still very noteworthy, and are often seen as precursors to the beliefs of the Protestant Reformation.

10th Century- The Macedonian/Byzantine Renaissance

Gregory of Narek

Theological Legacy: Mystic of Divine Mercy
Dates: 945-1011
Location: Narek Monastery, Armenia (modern day eastern Turkey)
Position: Monk, theologian
Influenced by: Neoplatonism, Pseudo-Dionysius the Areopagite
Key Concepts:

Divine mercy
Repentance and humility
Mystical union with God
Human sinfulness and the necessity of grace
Prayer as the path to spiritual transformation
The universal struggle of the soul before God

Major Works:

Book of Lamentations

Commentary of the Song of Songs
Influenced: Nerses Shnorhali, Armenian Apostolic Tradition
Titles/Honors: Saint, Doctor of the Church
Canonized: Yes. Pre-Congregation
Summary: He is considered the greatest theologian of the 10th century, most famous for his devotional writing the Book of Lamentations. In this book he explores many deep theological topics such as the inner soul and the necessity of constant prayer and repentance to keep the soul purified. He also emphasized God's divine mercy and putting total trust and faith in his plan. He was very influential on the Armenian Apostolic Church as well as their literature (similar to the role Dante played on Italian literature). He was just recently declared a Doctor of the Church for his many contributions to Christian theology (specifically the necessity of prayers and God's divine mercy).

11th century- The Great Schism of East and West

Peter Damian

Theological Legacy: Champion of Gregorian Reform
Dates: 1007-1072
Location: Ravenna, Italy
Position: Benedictine monk, Prior of Fonte Avellana, Cardinal-Bishop of Ostia
Influenced by: St. Romuald, Desert Fathers, Benedictine tradition
Key Concepts:

Reform of the clergy and church
Opposition to simony (buying and selling of church offices)
Enforcement of clerical celibacy
Monastic renewal and ascetic discipline
Papal authority and church unity
Personal holiness as the basis for church reform

Major Works:

Book of Gomorrah- critique of clerical immorality
Liber Gratissimus- opposing simony
Life of St. Romuald
170 letters and 53 sermons

Influenced: Gregorian reform movement, Pope Gregory VII
Major Opponents: Corrupt clerics
Titles/Honors: Saint, Doctor of the Church,
Canonized: Yes. Pre-Congregation
Summary: He is considered one of the principal architects of the 11th century Gregorian reform that sought to clean up the corruption, simony, as well as noncelibate clergy within the church. Influenced by the Desert Fathers and Benedict of Nursia, he preferred to ascetic lifestyle of self-discipline and personal holiness. However due to his knowledgeable letters and sermons on theology, he was frequently called upon by the church authority to help administer reform. The basis of his reformative approach, was that the change began with personal holiness and not so much the church as a whole. He is considered as laying the groundwork for the Gregorian Reform and the First Lateran Council, which settled matters of church independence, simony, and clerical celibacy. For this great contribution he is recognized as a doctor of the church.

Bernard of Clairvaux

Theological Legacy: Doctor of Divine Love
Dates: 1090-1153
Location: Burgundy, France
Position: Cistercian monk, abbot, theologian
Influenced by: The Rule of St. Benedict, Stephen Harding
Key Concepts:

Love of God as the center of the Christian life
Mystical union with Christ
Humility and self-denial
Devotion to the Virgin Mary
Monastic reform and renewal
Grace and free will working together

Major Works:

On Loving God
Sermons on the Song of Songs
Apologia to Abbot William
On Grace and Free Choice
On Consideration

Influenced: The Cistercian Order, Pope Eugene III, Thomas Aquinas
Major Opponents: Peter Abelard, Antipope Anacletus II
Titles/Honors: Saint, Doctor Mellifluus (Honey-Sweet Doctor), Doctor of the Church
Canonized: Yes. 1174 by Pope Alexaner III
Summary: He was one of the most influential monks of the early Middle ages, renown for his theological concepts but he also played a major role in political and ecclesiastic affairs. As a monk he first helped expand the Cistercian movement across Europe and eventually became abbot there. During this time, he wrote on the theological topics of love for God, humility, grace, and devotion to Mary. He also helped shape mystical theology and medieval spirituality. As he grew famous, he became an advisor to popes, kings, and church leaders. For his many contributions to theological development he is regarded as one of the great doctors of the church.

Hildegard of Bingen

Theological Legacy: Visionary of Divine Wisdom
Dates: 1098-1179
Location: Bermersheim, Holy Roman Empire
Position: Benedictine nun, abbess, theologian
Influenced by: Benedictine life, Jutta of Sponheim
Key Concepts:

Divine visions and revelation
Harmony of creation and the cosmos
Viriditas (spiritual vitality)
The relationship between humanity and God
Sacred music as a reflection of heavenly reality
Holistic views of nature, medicine, and spirituality

Major Works:

Know the Ways
Book of Life's Merits
Book of Divine Works
A morality play
Physica
Causae et Curae
Numerous hymns, songs, letters, and poems

Influenced: Medieval mysticism, Christian sacred music
Titles/Honors: Saint, Doctor of the Church
Canonized: Yes. 2012 by Pope Benedict XVI
Summary: She was one of the most gifted Christian polymaths of the middle ages well versed in theology, music, science, preaching, and writing. During most of her life as a nun she had many mystical visions of which she wrote about and encouraged the practice of spiritual mysticism. Similar to St. Bernard she became well revered during her lifetime, and corresponded with popes, emperors, bishops, and other political leaders. She is regarded as one of the most important female theologians in history. Quite interesting she was only recently canonized and declared a doctor of the church by Pope Benedict in 2012.

Berenger of Tours

Theological Legacy: Challenger of Transubstantiation
Dates: 999-1088
Location: Tours and Angers, France
Position: Theologian, Head of the School of Saint-Martin at Tours
Influenced by: Fulbert of Chartres, Augustine of Hippo, Ratramnus of Corbie
Key Concepts:

Authority of scripture on all theological matters
Use of reason in theology
Emphasis on spiritual and symbolic presence of Christ in the Eucharist
Critical of Transubstantiation teachings

Major Works:

On the Sacred Supper
Varios letters and writings connected to the Eucharist controversary
Influenced: Scholastic theology, Eucharistic doctrine

Major Opponents: Lanfranc of Bex, Pope Leo IX, Humbert of Silva Candida
Canonized: No. His views on the Eucharist were later condemned
Summary: He was the headmaster of one of the most important cathedral schools during the early middle ages (School of Saint-Martin in Tours, France). He is best known as one of the early challengers of the transubstantiation concept (Christ's actual presence in the bread and wine). Similiar to Ratramnus of Corbie he argued that Christ was not physically present in the Eucharist, rather spritiual and symbolically. This of course was the view of most rationalist theologians who favored reason on this matter. Berenger also emphasized that scripture was the primary authority on all theology, thus opposing the church's authority. Both his main concepts (against the transubstantiation and in favor of Sola Scriptura) were ultimately condemned by the Catholic Church yet became precursors to the practice of Scholasticism as well as the beliefs of the Protestant Reformation.

Anselm of Canterbury

Theological Legacy: Father of Scholasticism
Dates: 1033-1109
Location: Kingdom of Burgundy, Bec Abbey in Normandy, and Archbishop of Canterbury in England
Position: Benedictine monk, Abbot of Bec, Archbishop of Canterbury, Philosopher, Theologian
Influenced by: Augustine of Hippo, Neoplatonism, Lanfranc of Bec
Key Concepts:

Faith seeking understanding
Ontological Argument for the existence of God
Satisfaction Theory of Atonement
Harmony of faith and reason
Divine attributes, truth, freedom, and justice
Early Scholastic method

Major Works:

Monologion
Proslogion
Why God Became Man
On Truth
On Free Choice
On the Fall of the Devil

Influenced: Thomas Aquinas, Scholasticism, Bonaventure, Duns Scotus, Rene Descartes
Major Opponents: William II Rufus and Henry I during Investiture Controversary, Gaunilo
Titles/Honors: Saint, Magnificent Doctor, Doctor of the Church
Canonized: Yes. 1494 by Pope Alexander VI
Summary: He is regarded as the Father of Scholasticism during the middle ages, using a scholarly approach to merge faith with reason (often referred to as Faith seeking understanding). His most famous philosophical concept was his Ontological theory, which claimed God's existence was real since it could be conceived and a real existence was greater than only a concept (similiar to Descarte's theory "I think therefore I am"). Anselm also introduced the Theory of Atonement which claimed humanity created a debt to God thru Adam's sin, and that debt was restored thru the sacrificial death of Jesus Christ. The death of Christ redeemed humanity, however humans must still practice faith, repentance, prayer, and grace to achieve salvation. Many of Anselm's philosophical concepts were challenged, but he is considered among the greatest Christian philosophers that went on to inspire other great philosophers such as Thomas Aquinas and Rene Descartes.

Peter Abelard

Theological Legacy: Advocate of Inquiry
Dates: 1079-1142
Location: Nantes, France
Position: Scholastic philosopher, theologian
Influenced by: Roscellinus of Compiegne, William of Champeaux, Anselm of Laon
Key Concepts:

Scholastic method using faith and reason
Conceptualism (reality is formed as a concept in our minds)
Moral intention as the basis of ethical responsibility
Moral Influence in the Theory of Atonement

Major Works:

Yes and No
Know Thyself/Ethics
Theologia
History of My Misfortunes
Dialogue between a Philosopher, a Jew, and a Christian

Influenced: Thomas Aquinas, John of Salisbury, Scholasticism
Major Opponents: Bernard of Clairvaux, William of Champeaux, Council of Sens
Canonized: No. Many of his concepts were later condemned
Summary: He is considered another key founder of the school of Scholasticism behind Anslem of Canterbury. He encouraged the practice of doubt and questioning to seek the truth thru careful analysis. He also added to Anselm's Theory of Atonement by claiming human hearts were transformed thru Christ's death as the ultimate act of love. This theory of Moral Influence was later condemned by the church who saw Christ's death as having much deeper meaning then just an act of Love that changed humanity. It not only changed humanity but also changed our standing before God who had now forgiven us after the death of Christ. Critics also pushed back on Albelard's approach to encourage that people question their faith and find answers on their own. This was seen as a form of rejection of the church's teaching and authority. Many of his concepts were officially condemned at the Council of Sens. Nonetheless Abelard's scholastic approach of questioning, examining, and using reason are still used in most seminars and universities.

12th century- The Birth of Scholasticism

Peter Lombard

Theological Legacy: Systematic Theologian
Dates: 1095-1160
Location: Novara, Lombardy (Italy)
Position: Scholastic theologian, professor of Notre Dame, Bishop of Paris
Influenced by: St. Augustine of Hippo, Peter Abelard, Hugh of St. Victor
Key Concepts:

The Holy Spirit is the Love between the Father and the Son
Systematic organization of Christian theology
Scholastic method of organizing authoritative theological opinions
Clarification of the seven sacraments

Major Works:

Four Books of Sentences
Magna Glossatura (commentary on Pauline Epistles)
Biblical commentaries and sermons

Influenced: Thomas Aquinas, Bonaventure, Albert the Great, Duns Scotus, William of Ockham
Major Opponents: Joachim of Fiore, (criticism over several of his concepts mainly on the Trinity)
Titles/Honors: Master of the Sentences
Canonized: No.
Summary: He is considered the primary catechist of the middle ages, who systematically organized all theological concepts and doctrine into his Four Books of Sentences. This became the primary textbook of theological Christian study for several hundred years (before Aquinas' Summa Theologica). This textbook was considered the foundational blueprint that inspired later scholastic theologians such as Thomas Aquinas, Bonaventure, and Pope Benedict XVI. He also famously standardized the seven sacraments that became official doctrine at the Council of Florence (1439) and Council of Trent (1547). Despite these great contributions some of Lombard's concepts were rejected by the Orthodox church such as the Holy Spirit's role in the Trinity as the embodiment of love.

Peter of Bruys

Theological Legacy: Critic of Infant Baptism
Dates: 1117-1131
Location: Bruis, Dauphine (southeastern France)
Position: Former Catholic priest, religious reformer, theologian, and founder of the Petrobrusian movement
Influenced by: Gundolfo, The Gospels
Key Concepts:

Rejection of infant baptism
Baptism should allow personal faith
Rejection of the Mass as a repeated sacrifice
Opposition to transubstantiation
Rejection of Purgatory and prayers for the dead
Rejection of veneration of the cross
Rejection of veneration of holy sites and church buildings
Scripture authority over ecclesiastical authority

Influenced: The Petrobrusians, Henry of Lausanne, Henrician movement
Major Opponents: Peter the Venerable, Peter Abelard, Roman Catholic authorities, the Inquisition
Titles/Honors: Founder of the Petrobrusians
Canonized: No. Deemed a heretic
Summary: He was one of the earliest reform movements during the early ages that were condemned as heresy by the Roman church. Peter of Bruys emphasized the authority of scripture over the church and also challenged many of the orthodox teachings. His most controversial concept was against baptizing infants since they had no say in the matter, and should be allowed to decide for themselves. He completely rejected the practice of Eucharist and the transubstantiation based on his scriptural interpretations. Bruys also rejected the concept of Purgatory, and that souls could be saved thru prayers from the living. Many of these concepts were very challenging to the authority of the church and introduced new schisms that had not been seen since the 400s. The Petrobrusian movement was quickly condemned as heresy and hunted by the Inquisition. Peter of Bruys was eventually condemned and burned as a heretic. Although it's movement eventually died out many of Peter of Bruy's concepts could be seen as precursors to the Protestant Reformation.

Henry of Lausanne

Theological Legacy: Critic of the Clergy
Dates: 1116-1148
Location: Lausanne, Pitiers, Bordeaux, Toulouse (southern France)
Position: Benedictine monk, preacher, founder of Henrician Movement
Influenced by: Monastic ideals, Scripture, Peter of Bruys
Key Concepts:

Emphasis on personal faith, repentance, and moral reform
Criticism of clergy corruption
Rejection of infant baptism
Rejection of Purgatory and prayers for the dead
Rejection of the veneration of the cross
Opposition to ecclesiastical authority, liturgical ceremonies, and sacramental practice

Influenced: The Henricians
Major Opponents: St. Bernard of Clairvaux, Hildebert of Lavardin, Pope Innocent II, Peter the Venerable, Church authorities, Inquisition
Titles/Honors: Founder of the Henricians
Canonized: No. Deemed a heretic
Summary: He was another influential reformer during the middle ages, based out of southern France (the same region that produced the Cathars, the Petrobrusians, and the Waldensians) . His beliefs mostly aligned with Peter of Bruys in rejecting infant baptism, Purgatory, the liturgy, and sacramental practice. He was also very critical on the corruption of the church and rejected their authority in favor of scripture. He was known as a great preacher who attracting many to follow him, which eventually came to the attention of the church authorities such as Bernard of Clairvaux. He was ultimately arrested and condemned of heresy and his movement eventually faded out. Nonetheless his concepts were major seeds to the Protestant Reformation which emphasized scripture over church authority.

Peter Waldo

Theological Legacy: Advocate of Apostolic Poverty
Dates: 1140-1207
Location: Lyon, France
Position: Lay preacher, founder of Waldensian movement
Influenced by: Church fathers and scripture
Key Concepts:

Apostolic poverty
Lay preaching
Vernacular access to Scripture
Simplicity of Christian Life
Obedience to God over ecclesiastical authority
Evangelism by ordinary believers

Influenced: Waldensian Movement
Major Opponents: Archbishop Jean Bellesmains of Lyon, Pope Lucius III, the Inquisition
Titles/Honors: Founder of the Waldensians
Canonized: No. Deemed a heretic
Summary: He was one of the first major heretics of the Middle Ages, who promoted the concept of Scripture as the primary authority over the church. He also emphasized the practice of simple living, manual labor, and poverty as a means to get closer to God. Both these concepts were seen as major precursors to the Protestant Reformation. The Waldensian Movement was eventually condemned as heresy, it's followers were excommunicated from the church. It's heretical movement was even hunted by the newly established Inquisition. Despite all this persecution the Waldensians survived to later align itself with the Protestant Reformation.

Dominic de Guzman

Theological Legacy: Scholar of Preaching
Dates: 1170-1221
Location: Caleruega, Kingdom of Castile (modern day Spain)
Position: Priest, preacher, founder of Dominican Order
Influenced by: St. Augustine, Canons Regular at Osma, Bishop Diego de Acebes of Osma
Key Concepts:

Preaching and evangelization
Defense of orthodox Christian doctrine
Scholarly study of scriptures and theology
Emphasis on poverty and simplicity
Contemplation leading to action

Influenced: The Dominican Order, St. Thomas Aquinas
Major Opponents: The Albigensians (Cathars)
Titles/Honors: Saint, Founder of the Dominicans
Canonized: Yes. 1234 by Pope Gregory IX
Summary: He is best known as the founder of the Dominican Order, one of the most popular Christian Orders alongside the Franciscans and Benedictines. St. Dominic put an emphasis on academic discipline and study, seeing knowledge and reason as a path to spiritual enlightenment. He also emphasized the monastic ideals of simplicity, isolation, poverty, and constant prayer. He wrote many scathing attacks against heretical Christian branches most notably the Cathars. He played a major role in the development of his ideals, thru preaching and evangelizing across western Europe (Spain and France). Many great theologians and doctors of the church were Dominicans, such as Thomas Aquinas, St. Albert the Great, and St. Catherine of Siena.

Francis of Assis

Theological Legacy: Brotherhood of Creation
Dates: 1181-1226
Location: Assisi, Italy
Position: Friar, priest, founder of Franciscan Order
Influenced by: Scripture, New Testament
Key Concepts:

Poverty
Humility
Charity and service to the poor
Peace and reconciliation
Love of creation and all living things
Imitation of Christ

Major Works:

The Rule of St. Francis
Earlier Rule
Canticle of the Creatures

Influenced: The Franciscan Order, St. Clare of Assisi and the Poor Clares
Titles/Honors: Saint, Founder of the Franciscans, Patron Saint of Animals
Canonized: Yes. 1228 by Pope Gregory IX
Summary: He is best known as the founder of the Franciscan Order, often seen as the altering view point to the Dominicans. Instead of scholarly pursuit like the Dominicans, the Franciscans emphasize more of a social interaction with the poor and all of nature. They also lived a monastic life of simplicity, poverty, and humility seeking to imitate the life of Christ. Saint Francis is especially famous for his unique connection to animals and nature which would classify him as somewhat of a mystic. He promoted the goodness of God's creation, and that humanity should live in brotherhood to always support and love one another.

Alexander of Hales

Theological Legacy: Pioneer of Scholastic Theology
Dates: 1185-1245
Location: Gloucestershire, England
Position: Theologian, philosopher, Theologian teacher at University of Paris, Franciscan friar
Influenced by: Augustine of Hippo, Anselm of Canterbury, Aristotelian philosophy, Franciscan spirituality
Key Concepts:

Divine illumination in human knowledge
Primacy of grace
Theology as wisdom ordered toward God
Scholastic method and systematic theology
Integration of Augustinian theology with academic reason
Development of Franciscan tradition

Major Works:

Summa Universae Theologiae
Commentary on Peter Lombards Sentences

Influenced: Bonaventure, John of La Rochelle, Duns Scotus
Titles/Honors: The Irrefutable Doctor
Canonized: No.
Summary: He is considered one of the founding fathers of the Franciscan Order and a pioneer of the academic practice of scholasticism in theology. As Master of Theology at the acclaimed University of Paris, he was considered one of the top theologians during the Middle Ages. Heavily influenced by Augustine he incorporated many of his teachings into a form of systematic theology. He encouraged the practice of scholasticism while also emphasizing the importance of love and grace to achieve divine illumination. Although he played an important role in shaping academic theology, including inspiring the great Bonaventure, he never quite achieved holy status, perhaps the reason he was never canonized.

Anthony of Padua

Theological Legacy: Doctor of Evangelization
Dates: 1195-1231
Location: Lisbon, Portugal
Position: Franciscan friar, priest, theologian, preacher
Influenced by: St. Francis of Assisi, Augustine of Hippo
Key Concepts:

Evangelical poverty and simplicity
Biblical preaching and teaching
Repentance and conversion
Compassion for the poor and marginalized
Defense of orthodox Christian doctrine against heresy

Major Works:

Sunday Sermons
Festal Sermons

Influenced: The Franciscan Order
Major Opponents: Albigensian Cathers
Titles/Honors: Saint, Doctor of the Church, Evangelical Doctor, Patron Saint of lost items
Canonized: Yes. May 1232 by Pope Gregory IX
Summary: He was originally an Augustinian canon and later became a Franciscan friar after being inspired by the martyrdom of Franciscan missionaries in Morocco. He is known for his great preaching and deep knowledge of the scripture, which attracted large crowds throughout his travels. He preached compassion for the poor, repentance, and living a life of humility, poverty, and simplicity. He also defended the faith against heretical movements, most notably the Albigensians in southern France. He is associated with many miracles and deep meditative practices often associated with spiritual mysticism. He is considered the patron saint of lost things, which is a reference to a book of psalms he had lost and found while preaching in Bologna. Anthony was so inspired by the Franciscan martyrs, that he too hoped to become a missionary martyr. Although he did come at odds with the Cathars, he ultimately died at the young age of 35 due to illness and exhaustion.

13th Century- Scholasticism: The Integration of Faith and Reason

Albert Magnus the Great

Theological Legacy: Doctor of Christian Aristotelianism
Dates: 1200-1280
Location: Lauingen, Swabia (present day Bavaria, Germany)
Position: Dominican friar, theologian, philosopher, scientist, Bishop of Regensburg
Influenced by: Aristotle, Christian theology, Greek philosophy
Key Concepts:

Integration of faith and reason
Christian Aristotelianism
Natural law
Empirical study of nature
Systematic analysis of the natural sciences

Major Works:

Summa Theologiae
Summa de Bono
Commentaries on Aristotles' writings
Writings on natural science, zoology, botany, mineralogy, astronomy, and theology

Influenced: St. Thomas Aquinas (his student), Medieval Scholasticism
Major Opponents: Critics of Aristotelian philosophy
Titles/Honors: Saint, "Great", Doctor of the Church, Patron Saint of scientists and philosophers
Canonized: Yes. 1931 by Pope Pius XI
Summary: He was a Dominican friar and an academic extraordinaire, who practiced the scholastic approach of uniting faith with reason. He integrated Greek philosophy, most notably the teachings of Aristotle, into theological understanding. He also promoted the study of natural science as a vital connection to Christianity. His writings on science, philosophy, and theology became primary textbooks in seminars and unviersities. He later became known as the Doctor Universalis for all his contributions in a wide array of scientific fields. Perhaps his greatest claim to fame was being the teacher of St. Thomas Aquinas, who went on to become one of the greatest Christian theologians of all time. Quite interesting, he was first honored more as a scientist and philosopher long before he was recognized as a true Doctor of the Church (hence the delayed canonization).

Bonaventure

Theological Legacy: Doctor of the Spiritual Journey
Dates: 1217-1274
Location: Bagnoregio, Papal States (modern day Italy)
Position: Francisican friar, theologian, philosopher, Cardinal-Bishop of Albano
Influenced by: St. Francis of Assisi, Augustine of Hippo, Pseudo-Dionysius, Anselm of Canterbury, Alexander of Hales
Key Concepts:

The soul's journey to God
Divine illumination
Exemplarism (all creation reflects divine ideas)
Integration of faith, reason, and mysticism
Christ as the center of creation and redemption
True enlightenment achieved thru union with God

Major Works:

The Journey of the Mind into God
Commentary on the Sentences
Breviloquium
The Tree of Life
The Major Legend of St. Francis
Collations on the Six Days

Influenced: Duns Scotus, Peter John Olivi, Dante Alighieri, Nicholas of Cusa, John of the Cross
Major Opponents: Critics of the Franciscan Order
Titles/Honors: Saint, "Seraphic Doctor", Second Founder of the Franciscans, Doctor of the Church
Canonized: Yes. 1482 by Pope Sixtus IV
Summary: He is considered the second most important founding member of the Franciscans after Francis of Assisi. However his contribution to theology was far greater then St. Francis, which later earned Bonaventure the title of Doctor of the Church (a title Francis of Assisi did not receive). Bonaventure leaned more into faith and spirituality vs the scholastic approach of science and reason. While he still supported the scholastic method his ultimate claim was that true knowledge could only be achieved thru meditation, prayer, love, and a mystical union with God. Many of his theological concepts dealt with the practice of mysticism, spirituality, and even exemplarism (which traces all creation as part of God's plan). He also played a major role in shaping and leading the Franciscan Order after St. Francis. He is referred to as the Seraphic Doctor for his concept of the soul's journey to God, which emphasizes love over the pursuit of the knowledge.

Thomas Aquinas

Theological Legacy: Architect of Scholasticism
Dates: 1225-1275
Location: Roccasecca, Kingdom of Sicily (modern day Italy)
Position: Dominican frair, theolgoian, philsopher, Professor at the University of Paris and University of Naples
Influenced by: Aristotle, Augustine of Hippo, Boethius, Pseudo-Dionysius, Albert Magnus the Great (his teacher)
Key Concepts:

Harmony of faith and reason
Natural law
The Five Ways (arguments ofr God's existence)
Analogy of being (God is goodness an all goodness comes from God)
Essence and existence distinction
Virtue ethics
Divine simplicity
Thomistic metaphysics
Principle of double effect (where sins pertaining to self-defense, military actions, or even medical procedures could be forgiven)

Major Works:

Summa Theologiae
Summa Contra Gentiles
Commentary on the Sentences
On Being and Essence
Eucharistic Hymns (Pange Lingua and Tantum Ergo)

Influenced: Thomism, Duns Scotus, Francisco Suarez, Jacques Maritain, Etienne Gilson, Pope Leo XIII, Catholic theology
Major Opponents: Latin Averroists (Muslim philosophy movement), critics of Scholasticism
Titles/Honors: Founder of Thomism, Doctor Angelicus, Doctor Communis, Doctor of the Church, Patron Saint o students and universities
Canonized: Yes. 1323 by Pope John XXII
Summary: He is considered the greatest Christian theologian alongside Augustine of Hippo. He began as a Franciscan friar in pursue of knowledge thru the Scholastic approach which he learned from the Gret Albert Magnus. He eventually established his own school of thought that later became known as Thomism. This included a union of faith and reason, that explored the existence of God, the existence of humanity, our essence, virtues, metaphysics, and divine simplicity. His most famous work, The Summa Theologiae, became the primary source of Christian doctrine throughout the Middle Ages (before the Catechism was introduced in 1992). His Five Way theory explained God's existence thru the theory of motion (where God was the primary source), the theory of cause and effect (where God was the primary cause), the theory of Contingency (existence traces it's roots to a primary existence which is God), Theory of Perfection (where God was the source of all goodness, truth, and perfection), Theory of Teleolgy (there is a purpose for this existence, and the source of that purpose comes from God). Aquinas developed so many groundbreaking philosophical concepts using reason, to explain many of the mysteries of faith. For this reason he is considered one of the greatest Church Doctors in Christian history.

Meister Eckert

Theological Legacy: Mystic of the Divine Ground
Dates: 1260-1327
Location: Thuringia, Strasbourg, Cologne, and Paris
Position: Dominican friar, priest, theologian, philosopher, Master of Theology at University of Paris
Influenced by: Thomas Aquinas, Albert Magnus the Great, Pseudo-Dionysius the Areopagite, Neoplatonism
Key Concepts:

Detachment of self-will and possessions
Birth of God in the Soul- divine becomes present within the purified soul
Ground of the Soul- deepest center of the soul where union with God occurs
Breakthrough- transcending ordinary distinctions to encounter the Godhead
Union with God- the soul's ultimate spiritual fulfillment

Major Works:

Talks of Instruction
Book of Divine Consolation
On Detachment
The Nobleman

Influenced: Johannes Tauler, Henry Suso, Nicholas of Cusa, Jakob Bohme
Major Opponents: Franciscan theologians, The Inquisition
Titles/Honors: "Meister" as Master of Theology at University of Paris
Canonized: No. Some of his teachings were condemned
Summary: He was a theologian who encouraged the practice of Christian mysticism as a form to get closer to God. His greatest concept was revolved around the inner soul, where detachment was required to achieve a high connection with God. He believed one must let go of their ego and self-interests and practice deep prayer and meditation to access their divine soul. He also believed the soul had a "Ground" that was uncreated like the rest of the human body. This theory essentially favored a form of pre-existence in which the soul already had some divine essence to it, which was considered controversial and later deemed heresy. Despite his condemned teachings on the divine presence of the soul, he is still regarded as one of the most influential Christian mystics.

John Duns Scotus

Theological Legacy: Philosopher of Individualism
Dates: 1265-1308
Location: Berwickshire, Scotland
Position: Franciscan friar, priest, theologian, philosopher, professor
Influenced by: St. Augustine, Aristotle, St. Bonaventure, Henry of Ghent, William of Ware
Key Concepts:

Univocity of Being- the term existence means the same for anything (Divine or worldly)
Haecceity (This-ness)- What makes a thing unique
Formal Distinction- The distinction between two items within one thing (such as a person's will or intellect)
Voluntarism- The Primacy of will, both divine and human
Defense of the Immaculate Conception of Mary

Major Works:

Ordinatio
Reportatio Parisiensis
Lectura
Quodibetal Questions
On the First Principle

Influenced: William of Ockham, Francisco Suarez, Scotism
Major Opponents: Thomists (Followers of Aquinas)
Titles/Honors: Blessed. The Subtle Doctor.
Canonized: No. However he was beatified by Pope John Paul II in 1993
Summary: He is considered one of the most important theologians of the middle ages, often seen as a rival to many of Thomas Aquinas' concepts. For starters he felt the term "exists" was the same across the board whether God, human, or anything else that exists in reality. This went against Aquina's theory of analogy of being which emphasized that God existed in a different way then humans or animals. Scotus also introduced the concept of haecceity where everything is its own thing, even if it shares identical traits. This put more emphasis on individuality over universality. He also pioneered the concept of formal distinction which are seen as two aspects that are genuinely different, but are also part of the same thing (such as God's justice and God's mercy). Scotus is ultimately seen as an individualist champion, who emphasized freedom and the power of the will over rationality. He was even a firm supporter of the Immaculate Conception, and argued that as soon as Mary conceived Christ she was eternally preserved from sin. Even though he was not officially canonized his theological teaching is still highly revered by the church to this day as one of the greatest Christian philosophers.

William of Ockham

Theological Legacy: Philosopher of Nominalism
Dates: 1287-1347
Location: Surrey, England; Bavaria, Holy Roman Empire
Position: Franciscan friar, philosopher, theologian
Influenced by: Aristotles, Anselm of Canterbury, Thomas Aquinas, Duns Scotus, Peter Abelard, Petrus Aureolus, Durandus of Saint-Pourcain, Henry Harclay
Key Concepts:

Ockham's Razor: Explanations should not multiply entities beyond necessity
Nominalism: Universals do not exist independently; only individual things are real
Empiricism: Knowledge begins with experience
Theological Voluntarism: God's will is primary in moral and theological matters

Major Works:

Summary of Logic
Commentary on the Sentences
Quadlibetal Questions
Dialogus
Opus Nonaginta Dierum

Influenced: Jean Buridan, Adam de Wodeham, John Wycliffe, Martin Luther
Major Opponents: Pope John XXII
Titles/Honors: Venerable Veginner, Invincible Doctor
Canonized: No.
Summary: He is considered one of the early advocates of knowledge thru experience over spiritual or even scholastic methods. He also promoted the concept of nominalism, which put more emphasis on the individual over the universal group (similar to Duns Scotus). Perhaps Ockham's greatest philosophical concept is his analysis method referred to as Ockham's Razor. This is a philosophical approach that seeks to focus on the simple truth, without extending or over-complicating it. This especially applies when multiple concepts or principles are added to a general theory. In Ockham's rule it is best to use the concept with less assumptions (the simpler version). Ockham generally considered experience, faith, and revelation over scholastic reason. This viewpoint could be seen as a precursor to the Protestant movement, who ultimately rejected reason in favor of the scripture and faith alone. Many of his philosophical ideas influenced scientific development and also the Protestant Reformation.

14th Century- Mysticism and Early Reform

Bridget of Sweden

Theological Legacy: Mystic of Divine Revelation
Dates: 1303-1373
Location: Uppland, Sweden
Position: Swedish noblewoman, mystic, reformer of the church
Influenced by: Christian mysticism, Franciscan Order, Cistercian Order
Key Concepts:

Mystical revelations
Devotion to the Pasion of Christ
Church reform and moral renewal
Papal return from Avignon to Rome
Charity, pilgrimage, penance, and holy living
Lay holiness within marriage and family life

Major Works:

Revelationes- Collection of the visions and messages she received

Influenced: The Bridgettine Order, Christian mysticism
Major Opponents: Church officials against reform, Supporters of Avignon Papacy
Titles/Honors: Saint, Founder of the Bridgettines, Patron Saint of Sweden
Canonized: Yes. 1391 by Pope Boniface IX
Summary: She was one of the most famous theological laypeople, who was not a clergy member. As a wife and a mother of eight, she lived a very devout life to Christ and received many visions that further inspired her involvement. She dedicated much of her time in pray, charity, and holiness. She also became an influential voice with the church, calling for renewed charity, pilgrimage, and moral standards. She later established a sisterhood known as the Bridgettine Order and famously urged the papacy to return from Avignon to Rome. Her greatest theological contributions come in the development of mysticism, where she presented new vivid revelations of Christ's Passion, heaven, hell, divine judgement, and the need for spiritual growth.

John Wycliffe

Theological Legacy: Pioneer of Sola Scriptura
Dates: 1328-1384
Location: Yorkshire, England
Position: Catholic priest, theologian, philosopher, church reformer, professor at Oxford
Influenced by: Augustine of Hippo, Medieval scholasticism
Key Concepts:

Primacy of Scripture as the highest authority
Criticism of church wealth, corruption, and papal power
Opposition to transubstantiation
Vernacular access to the Bible (everyday native language; not just Latin)
True authority comes from righteousness and grace (not just the seat of power)

Major Works:

On Civil Dominion
On the Church
On the Truth of Holy Scripture
Trialogus
Wycliffe Bible (First complete English Bible)

Influenced: The Lollard movement, Jan Hus, English Reformation
Major Opponents: Pope Gregory XI
Titles/Honors: Morning Star of the Reformation, Evening Star of Scholasticism,
Canonized: No. Condemned as heretic
Summary: He is considered one of the first major reformist theologians of the late middle ages that served as a precursor to the Protestant movement (The Morning Star of the Reformation). As a priest, scholar, and professor at Oxford he was well versed in scripture and theology. He began to publicly criticize the church for its abuse of wealth, corruption, and authority. He claimed that authority should only come from righteous people and scripture. He also challenged other aspects of Catholic doctrine such as the Latin mass and the transubstantiation. He is one of the first persons to translate the bible into English. His followers became known as Lollards that went on to influence other reform movements such as the Hussites and eventually the Protestants. He was officially condemned posthumously at the Council of Constance in 1418. His followers eventually integrated with the Protestant movement.

Julian of Norwich

Theological Legacy: Mystic of Divine Mercy
Dates: 1343-1416
Location: Norwich, England
Position: Christian mystic, theologian, and anchoress
Influenced by: Augustine of Hippo. Christian mysticism
Key Concepts:

God's unconditional love and mercy
All shall be well
Christ as a nurturing mother figure
The ultimate triumph of divine love over sin and suffering
Hope, compassion, and the intimate relationship between God and humanity

Major Works:

Revelations of Divine Love

Influenced: Christian mysticism
Canonized: No.
Summary: Although she is not formally canonized she is recognized as one of the greatest female mystics of the Middle Ages (alongside Hildegard, Catherine of Sienna, and Teresa of Avila). In her most famous writing, Revelations of a Divine Love she shares the sixteen visions of Christ she experienced during her illness. In this writing she shared in great detail her experience of God, as someone who is limitless in love, mercy, and care. He is with us during the hardest of times, the trials and tribulations, and especially during suffering and sin. Her most famous phrase is that "all shall be well, and all shall be well, and all manner of things shall be well". This is a very affirming belief of hope and optimism that comes thru trust in the lord.

Catherine of Siena

Theological Legacy: Mystic of Self-Knowledge
Dates: 1347-1380
Location: Siena, Italy
Position: Dominican sister, mystic, theologian, church reformer
Influenced by: Dominican Order, St. Dominic, Thomas Aquinas, Augustine of Hippo
Key Concepts:

Union with God thru love
Transformation of the soul by grace
The "Cell of Self-Knowledge"
Divine Providence
Reform of the clergy and church
Papal authority
Christ as the mediatrix between God and humanity
Charity as the highest expression of spiritual life

Major Works:

The Dialogue of Divine Providence
Letters (400 letters to popes, rulers, clergy, and Christians)

Prayers and other writings
Influenced: Christian mysticism, Dominican spirituality, divine love
Major Opponents: Supporters of Avignon Papacy
Titles/Honors: Saint, Doctor of the Church, Patron Saint of Italy
Canonized: Yes. 1461 by Pope Pius II
Summary: She is one of the most revered female theologians and doctors of the church (alongside Hildegard of Bingen and Teresa of Avila). Despite having minimal education, she was blessed with deep faith and understanding of the scriptures and church tradition. Similar to Bridget of Sweden, Catherine also claimed mystical revelations, however Catherine provided much more theological depth in her written works. She emphasized divine love, grace, human freedom, and the soul's union with God. She also got involved with church ecclesiastic matters and helped persuade the papacy to move from Avignon back to Rome. Her greatest claim to fame is encouraging the practice of spiritual mysticism thru isolated prayer and meditation where one can achieve "self-knowledge" (union with God).

Jan Hus

Theological Legacy: Precursor of Church Reform
Dates: 1369-1415
Location: Bohemia, Holy Roman Empire (modern Czech Republic)
Position: Catholic priest, theologian, professor at University of Prague
Influenced by: John Wycliffe, Protestant Reformation
Key Concepts:

Supremacy of scripture over church corruption and authority
Reform of the clergy
Criticism of indulgences
True church consists of the faithful and not institutional hierarchy
Predestination and divine sovereignty
Communion for the laity under both bread and wine (at the time only bread was served to the laypeople, while the wine was only for the clergy)

Major Works:

On the Church
On Simon
On the Six Errors

Influenced: The Hussite movement, Bohemian Reformation, Protestant Reformation
Major Opponents: Church authorities, Archbishop Zbyynek Zajic, Pope Alexander V, Antipope John XXIII
Titles/Honors: Czech national hero, Bohemian reformer and martyr
Canonized: No. He was condemned a heretic
Summary: He is considered another of the major forerunner theologians to the Protestant Reformation (alongside John Wycleffe). His concepts mirror many of those presented by John Wycleff, only his movement was based in Czech vs Wyclffe's movement in England. Hus strongly advocated for the practice of mass in the local language of Czech and heavily opposed the practice of indulgences. He was also very outspoken on the authority of scripture and the righteous over the institutional hierarchy that had become corrupt. Unlike Wycliffe who was condemned posthumously, Hus was put on trial at the Council of Constance, and was declared a heretic. He was given a chance to recant, but stood firmly by his beliefs and was burnt at the stake. He was later considered a national hero and martyr to the Czech Hussite movement as well as the Protestant Reformation.

Thomas a Kempis

Theological Legacy: Advocate of Devotional Christianity
Dates: 1380-1471
Location: Dusseldorf, Rhineland (modern day Germany)
Position: Augustine Canon Regular, Priest, Teacher, and scribe
Influenced by: Augustine of Hippo, Thomas Aquinas, Saint Paul, Geert Groote, and Florens Radewyns
Key Concepts:

Humility
Self denial
Following Christ's example
Detachment from worldly ambition
Inner spiritual transformation
Patient suffering
Obedience
Prayer and contemplation
Eucharistic devotion

Major Works:

The Imitation of Christ

Influenced: Ignatius of Loyola, Thomas More, John Fisher, Therese of Lisieux, John Wesley, Thomas Merton
Canonized: No
Summary: Kempis was an Augustine canon, a priest living in the monastic community known as the Congregation of Windesheim. He is most famous for his writing, The Imitation of Christ which became one of most famous devotional writings of the Middle Ages, second only to the Bible. Thru this work Kempis shared a spiritual approach to living as Christ did. He emphasized the themes of humility, obedience, prayer, and self-denial in everyday life. This is considered a spiritual guide to fully devote oneself to Christ. It's not an institutional set of monastic Rules like Benedict wrote, but more so a theological approach that addresses the nature of the soul and the necessity of detachment from ambition and materialism. In a way it's quite similar to Therese of Lisieux's "Little Way" approach, which also demonstrates a method of getting closer to God.

15th Century- Humanism and Protestant Reformation

Nicholas of Cusa

Theological Legacy: Philosopher of the Infinitude
Dates: 1401-1464
Location: Kues, Trier, Holy Roman Empire (Modern day Germany)
Position: Catholic cardinal, bishop of Brixen, theologian, philosopher
Influenced by: Plato and neoplatonism, Plotinus, Pseudo-Dionysius, Augustine
Key Concepts:

Learned ignorance (accepting the limits of knowledge)
Coincidence of Opposites
Limits of human knowledge (Accepting faith)
Unity amidst diversity
Church reform and concord
Faith and reason working together

Major Works:

On Learned Ignorance
On Catholic Concordance
The Vision of God
The Peace of Faith

Influenced: Christian mysticism, Renaissance philosophy
Major Opponents: Johannes Wenck
Canonized: No.
Summary: He was a firm believer in accepting the incomprehensiveness of God. While he encouraged the pursuit of knowledge he also felt it was necessary to accept that in that pursuit one would reach limits and never truly understand all. He also introduced the concept of the Coincidence of Opposites, as a means to describe the infinitude of God (such as God is the beginning and the end, he is near and he is far, he is the maximum and the minimum). He is ultimately considered a mystical philosopher who called for unity in the Catholic Church amidst the Protestant Reformation. Even though he initially supported the controversial Conciliar Movement (where the council would have more authority then the pope) he still remained in good standing with the Catholic Church his entire life.

Erasmus of Rotterdam

Theological Legacy: Pioneer of Christian humanism
Dates: 1466-1536
Location: Rotterdam, Netherlands
Position: Catholic priest, theologian, humanist scholar
Influenced by: St. Jerome, Augustine, Origen, Lorenzo Valla, Cicero
Key Concepts:

Philosophy of Christ- emphasis on inner piety over external ritual
Ad Fontes- Returning to scripture, as the primary source
Christian humanism
Religious moderation and tolerance
Critique of scholasticism and scientific analysis
Free will (against Luther's doctrine bondage of the will)

Major Works:

The Praise of Folly
Handbook of a Christian Knight
Novum Instrumentum Omne
The Education of a Christian Prince
On Free Will

Influenced: Martin Luther, Philip Melanchton, Huldrych Zwingli, William Tyndale, John Calvin, Ignatius of Loyola
Major Opponents: Martin Luther (over free will), Scholastics who opposed humanism
Titles/Honors: Prince of the Humanists. Greatest scholar of the Northern Renaissance.
Canonized: No.
Summary: He integrated humanism with scripture to become one of the lead theologians of the Northern Renaissance. He considered the approach of scholasticism as too over-analytical and preferred faith and scripture as the primary source of truth. He was also very outspoken against clerical corruption and the practice of simony and indulgences. In the midst of all the reformist movements, Erasmus sought to simply revive the Catholic Church rather than break away from it. He was also strongly in favor of free will and fervently defended it against Martin Luther's concept of grace only thru God (predestination). For this reason, he was not deemed a heretic and remained a Catholic his entire life. Nonetheless, many of his concepts are seen as a bridge to the Reformist movement.

Martin Luther

Theological Legacy: Father of Protestant Reformation
Dates: 1483-1546
Location: Saxony, Holy Roman Empire (Present day Germany)
Position: Theologian, Augustinian friar, reformer, professor
Influenced by: Augustine of Hippo, Johann von Staupitz, William of Ockham
Key Concepts:

Justification by faith alone (sola fide)
Scripture as the final authority (sola scriptura)
Salvation by grace alone (sola gratia)
Priesthood of all believers
Critique of indulgences and church corruption
Two Kingdoms doctrine
Reform of church worship and practice

Major Works:

Ninety Five Theses
Address to the Christian Nobility of the German Nation
The Babylonian Captivity of the Church
Small Catechism
Large Catechism
German translation of the bible

Influenced: Philip Melanchthon, John Calvin, Martin Bucer
Major Opponents: Pope Leo X, Johann Tetzel, Johann Eck, Emperor Charles V
Titles/Honors: Father of the Protestant Reformation
Canonized: No. Declared a heretic
Summary: He is regarded as the father of the Protestant Reformation who openly challenge the corruption of the Catholic Church, by posting his ninety five theses manifesto on the church doors. Luther expanded on the earlier concepts of sola fida and sola scritpura as the backbone of his reformed movement. He went as far to state that even sacraments, acts of charity, and pilgrimages were not necessary if one practiced daily faith. Luther was also heavily influenced by the philosophy of Augustine of Hippo as was most relevant in his writing of the Two Kingdoms (somewhat based off the City of God). Luther explains that people live in two realms at once; a spiritual kingdom of God that is governed by scripture and God and a temporal kingdom that is governed by kings and governments. None of Luther's concepts were really original ones, however they were expressed with much more passion, directness, and challenging to the church. The movement quickly caught fire across central and northern Europe thanks to the invention of the printing press. He was eventually declared a heretic and excommunicated by the church. The catholic church eventually called the Council of Trent in 1545 as a response and revival effort in the wake of the Protestant Reformation. Despite his controversial reformation, it became one of the largest schism in Christian history, which today makes up 70-80 million followers.

Ignatius of Loyola

Theological Legacy- Master of Spiritual Discernment
Dates: 1491-1556
Location: Loyola, Spain
Position: Catholic priest, founder of Jesuit Order
Influenced by: Francis of Assisi, Ludolph of Saxony, Thomas a Kempis
Key Concepts:

Ignatian Spirituality
Spiritual discernment
Finding God in all things
For the Greater Glory of God
Spiritual Exercises
Obedience and missionary service

Major Works:

Spiritual Exercises

Influenced: Jesuit Order, Francis Xavier, Peter Faber, Catholic Counter Reformation
Major Opponents: Protestant Reformers
Titles/Honors: Saint, Founder of Jesuits
Canonized: Yes. 1622 by Pope Gregory XV
Summary: He is considered the first major theologian during the Catholic Revival (Counter Reformation) movement. He experienced a dramatic conversion during a battle where he found Jesus and decided to dedicate his life to him. After he became a priest he later established the Jesuit Order with the pope's blessing to begin missionary work, most notably into America and Asia. While this order became his claim to fame, he also made great contributions to Counter Reformation theology with an emphasis on living according to God's will, education, and service to others. His concept of spiritual exercises was to find God in all things and discussed the influences that draw people toward God and away from God.

16th century- Reformation and Counter-Reformation

John of Avila

Theological Legacy: Doctor of Christian Spirituality
Dates: 1499-1569
Location: Castile, Spain
Position: Spanish priest, mystic, theologian
Influenced by: Thomas Aquinas, Domingo de Soto
Key Concepts:

Deep union with Christ through prayer
Reform and renewal of the clergy
Centrality of the Eucharist
Conversion of heart and holiness of life
Spiritual direction and pastoral care
Evangelization through preaching

Major Works:

Listen, O Daughter
Treatise on the Priesthood

Influenced: St. Teresa of Avila, St. John of God, St. Francia Borgia, St Louis of Granada
Titles/Honors: Saint, Doctor of the Church, Apostle of Andalusia
Canonized: Yes. 1970 by Pope Paul VI
Summary: Also known as the Apostle of Andalusia he was a major theological leader during the Catholic Reformation based in Spain. He was an advocate of deep spirituality and a passionate preacher who worked to reform the clergy and well revered throughout Spain. He emphasized prayer, personal conversion, pastoral holiness, and the centralization of the Eucharist. He was also a friend of St. Ignatius of Loyola, worked closely with the Jesuits, and was a spiritual guide for Teresa of Avila. He is remembered as one of the main architects of the Catholic Revival alongside Charles Borromeo, and for this reason he is honored as a doctor of the church.

John Calvin

Theological Legacy- Architect of Reformed Christianity
Dates: 1509-1564
Location: Picardy, France; Republic of Geneva (Switzerland)
Position: French Protestant Reformer, Founder of Calvinism
Influenced by: Augustine of Hippo, Martin Luther, Erasmus, Jacques Lefevre d'Etaples
Key Concepts:

Sovereignty of God
Predestination
Election/Double Predestination (God choosing those who will be saved and damned)
Salvation by Grace
Total depravity of humanity
Covenant theology (God's covenant with Noah, Abraham, Moses, and through Christ)
Authority of Scripture
God's glory as the ultimate purpose of creation

Major Works:

Institutes of Christian Religion
Biblical commentaries

Influenced: Calvinism, Presbyterianism, Congregationalism, Puritanism, John Knox
Major Opponents: Roman Catholic authorities, Michael Servetus
Titles/Honors: Founder of Calvinism
Canonized: No. Deemed a heretic
Summary: He is considered the second most important figure of the Protestant Reformation after Martin Luther. While Luther is considered the founding father, John Calvin is considered the architect who laid out the systematic structure of this new reformed church. He supported the common Protestant concepts of Sola Scriptura, Sola Fida, salvation thru grace, and criticism of the Catholic corruption. His greatest theological contribution was the Sovereignty of God (God's governing rule over the universe, nature, humanity, life, human governments, and salvation). He also promoted the concept of double predestination which firmly claimed that God chose those who would be saved and those who would be damned. This strongly goes against the church's teaching that all had the free will to choose God. The concepts of Calvinism became the roots of many other church reform movements such as the Presbyterians, Congregationalists, and Puritans.

Teresa of Avila

Theological Legacy: Doctor of Mystical Prayer
Dates: 1515-1582
Location: Avila, Spain
Position: Carmelite nun, mystic, founder of the Discalced Carmelites
Influenced by: St. Augustine, St. Peter of Alcantara, St. John of Avila
Key Concepts:

Contemplative deep prayer
Mystical union with God
Interior transformation of the soul
Humility and detachment
Reform of religious life
Poverty, simplicity, and community life

Major Works:

The Life of Teresa of Jesus
The Way of Perfection
Interior Castle
The Book of Foundations

Influenced: St. John of the Cross, Discalced Carmelites
Major Opponents: Carmelite Order
Titles/Honors: Saint, Doctor of the Church, the Great Teresa
Canonized: Yes. 1622 by Pope Gregory XV
Summary: She is considered another champion theologian of the Catholic Reformation and one of the lead female mystical saints. As a Carmelite nun, she led a reformation on the order to address heavier discipline and devotion. She emphasized a life center on prayer to achieve a stronger mystical union with God. She also encouraged simplicity, poverty, and humility to live a complete religious life. She is one of the great female theologians that specialized in mysticism such as Hildegard, Bridget of Sweden, or Catherine of Sienna. Some of her writings are considered the greatest works of Christian mysticism which is why she was declared a doctor of the church.

Robert Bellarmine

Theological Legacy: Doctor of Counter Reformation Theology
Dates: 1542-1621
Location: Italy; Louvain, Belgium
Position: Jesuit priest, Professor of Theology at Roman College, Cardinal, Archbishop of Capua
Influenced by: St. Ignatius of Loyola, St. Thomas Aquinas
Key Concepts:

Defense of Catholic Orthodoxy against Protestantism
Authority of Papacy and the Church
Relationship between faith and reason
Reform and revival of the church
Grace, free will, and justification
Catechesis and theological education

Major Works:

Controversies of the Christian Faith (De Controversiis)
The Art of Dying Well
The Mind's Ascent to God
Catechism

Influenced: Catholic Counter Reformation
Major Opponents: Protestant Reformers, Calvinists, Lutherans, Michael Baius
Titles/Honors: Saint, Doctor of the Church
Canonized:
Summary: He was one of the key apologetics and theologians of the Catholic Counter Reformation, who defended the church against Protestant schismatic movements. Drawing on the Council of Trent he systematically analyzed Protestant doctrine and challenged all their concepts in his most famous writing De Controversiis. As a scholar, bishop, and cardinal many of his writings were very intellectual and influential in restoring Catholic theology. While advocating for church reform and education, he also reiterated the authority of the papacy. He integrated faith and reason in his theological writings, to appeal to a broader audience. He is also famous for his spiritual works, his concept of dying well, detachment from material things, meditation, and the mind's journey to God.

Peter Canisus

Theological Legacy: Doctor of Catholic Catechesis
Dates: 1521-1597
Location: Germany, Austria, Bohemia, Switzerland, Netherlands
Position: Jesuit priest, preacher, theologian, reformer
Influenced by: St. Ignatius of Loyola, St. Peter Faber, Council of Trent
Key Concepts:

Catholic renewal through education and catechesis
Reform without harsh polemics or personal attacks
Defense of Catholic doctrine against Protestant Reformation
Importance of preaching, sacraments, and spirituality
Marian devotion
Igantian spiritual practice

Major Works:

Summa Doctrinae Christianae
Catechismus Minor and Catechismus Maior
Influenced: Catholic revival, Jesuit education

Major Opponents: Protestant Reformer Theologians
Titles/Honors: Saint, Doctor of the Church, Second Apostle of Germany
Canonized: Yes. 1925 by Pope Pius XI
Summary: He is considered one of the leading Jesuit missionaries in Central Europe during the Catholic Revival (alongside Lawrence of Brindisi). He focused on better education and holiness for Catholics rather than attacking Protestant theology. He was very influential in establishing new Jesuit locations across Central Europe as well as colleges and seminaries. Canisus promoted the Ignatian concepts of spiritual discipline, discernment, and active ministry and evangelization. He also defended the importance of the sacraments (especially the Eucharist) as well as devotional practice to Mother Mary. Thru his tireless work of preaching and defending the church he is often considered the Second Apostle of Germany after St. Boniface.

Charles Borromeo

Theological Title: Champion of Counter Reformation
Dates: 1538-1584
Location: Milan, Italy
Position: Cardinal, Archbishop of Milan
Influenced by: Pope Pius IV (his uncle), Catholic reform, and humanism, St. Ignatius of Loyola, St. Philip Neri
Key Concepts:

Clerical reform and discipline
Seminary education for priests
Catechesis and religious education
Pastoral leadership and episcopal responsibility
Personal holiness through service and sacrifice

Major Works:

Roman Catechism
Letter, decrees, constitutions, and directives for clergy and laity

Influenced: Council of Trent, Confraternity of Christian Doctrine, St. Francis de Sales
Major Opponents: The Humiliati (religious order that plotted an assassination attempt against his reform efforts)
Titles/Honors: Saint
Canonized: Yes. 1610 by Pope Paul V
Summary: He is revered as the chief architect of the Catholic Reformation in response to the Protestant Reformation. Although he is seen more as an ecclesiastical reformer than a proper theologian, he still emphasized the necessity of prayer and spirituality. His reform addressed better education and discipline for priests and the laity. Borromeo also established the system of seminaries to better shape, mold, and train the future clergy members. Many of these reforms became official doctrine at the Council of Trent, which sought to revive the Catholic Church. This was ultimately done by weeding out the corruption, better education, and supporting new missionary evangelization orders such as the Jesuits.

John of the Cross

Theological Legacy: Doctor of the Dark Night
Dates: 1542-1591
Location: Avila, Spain
Position: Discalced Carmelite, mystic
Influenced by: St. Teresa of Avila, St. Thomas Aquinas
Key Concepts:

Dark Night of the Soul
Purification of the senses and spirit
Detachment from created things
Mystical union with God
Contemplative prayer
Divine love as the goal of spiritual life
The ascent of the soul toward God

Major Works:

Dark Night of the Soul
Ascent of Mount Carmel
Spiritual Canticle
Living Flame of Love

Influenced: St. Therese of Lisieux, Edith Stein, Thomas Merton, Pope John Paul II, Hans Urs von Balthasar, Discalced Carmelite Reform
Titles/Honors: Saint, "Mystical Doctor", Doctor of the Church
Canonized: Yes. 1726 by Pope Benedict XIII
Summary: He was a Spanish Carmelite mystic who worked closely with Teresa of Avila to reform the Carmelite Order. He is most renown for his works of poetry and theological writings pertaining to the soul's journey to God. He emphasized the concept that one must detach from material things to reach a closer spiritual union with God. He also popularized the concept of the Dark Night of the Soul, where it is normal to experience stages of empty prayer and conflicts of faith, in order to achieve higher union with God. He sees this phase as a purification process and part of the overall arching journey to achieve full mystical union with God. For this concept and many others, he is highly regarded as a doctor of the church.

Faustus Socinus

Theological Legacy: Pioneer of Unitarianism
Dates: 1539-1604
Location: Siena, Italy; Zurich, Basel, Transylvania, Krakow, and Luslawice (Poland)
Position: Theologian, humanist, leader of Polish Brethren, founder of Socinianism
Influenced by: Lealius Socinus (his uncle), Reform movements
Key Concepts:

Rejection of the trinity
Rejection of Christ's pre-existence
Christ as a unique holy and spiritual man, but not God himself
Reason in interpreting scripture
Free will and moral responsibility
Rejection of atonement and original sin
Faith expressed through obedience and moral living

Major Works:

On Jesus Christ the Savior
Explicatio Primae Partis Primi Capitis Evangelistae Johannis
On the Authority of Sacred Scripture

Influenced: The Polish Brethren, Socianism, Racovian Catechism, Transylvanian Unitarianism
Major Opponents: Roman Catholic theologians and authorities, Lutheran and Reformed Churches, Defenders of Nicene Orthodox
Titles/Honors: Founder of Socinianism, leader of Polish Brethren,
Canonized: No. Deemed a heretic by both Catholic and Protestant church
Summary: He is considered a radical Christian theologian that not only challenged the Catholic church but also the Protestant reformed churches. His principle concept was a total rejection of the Trinity and the Logos of Christ (similar to the early movement of Arianism). He also emphasized human freedom, free will, and moral responsibility. He rejected the concept of original sin, and thought it humanity should be responsible for their own choices and actions and not a form of inherited guilt from Adam and Eve. While he did not create a church movement, he laid the groundwork for many rational schools of thought, such as Socianism, and considered the founder of Unitarianism (the anti-Trinity belief that there is only one God). This theological belief of Unitarianism became very popular during the Enlightenment and Age of Reason.

Lawrence of Brindisi

Theological Legacy: Doctor of Biblical Exegesis
Dates: 1559-1619
Location: Brindisi, Italy
Position: Capuchin Franciscan, priest, theologian
Influenced by: St. Francis of Assisi
Key Concepts:

Defense of Catholicism during Counter-Reformation
Biblical preaching and scholarship
Apologetics against Protestantism and other schismatic opponents
Marian devotions
Church unity and reform

Major Works:

Mariale
Lutheranismi Hypotyposis
Biblical commentaries

Influenced: The Capuchin Order, Catholic Reformation
Major Opponents: Lutheran and Protestant movements
Titles/Honors: Saint, Doctor of the Church
Canonized: Yes. 1881 by Pope Leo XIII
Summary: He was an Italian Capuchin friar and renown theologian who played an important role during the Catholic Church's counter-reformation in response to Protestantism. He did most of his ministry work in Central Europe (Germany, Austria, and Bohemia) defended the Catholic doctrine thru careful biblical analysis. He also played a key role in strengthening the Capuchin Order throughout Central Europe. His writings and sermons promote Church unity, Catholic doctrine, and Marian devotions. Perhaps his greatest claim to fame was carrying a crucifix to rally the Christian troops against the Ottoman armies at the Battle of Szekesfehervar.

Francis de Sales

Theological Legacy: Doctor of the Devout Life
Dates: 1567-1622
Location: Savoy, France; Geneva, Switzerland
Position: Bishop of Geneva, missionary, founder of the Order of the Visitation
Influenced by: St. Charles Borromeo, Humanism
Key Concepts:

Universal call to holiness
Devotion in ordinary daily life
Gentleness and charity in evangelization
Divine love as the heart of the Christian life
Spiritual direction adapted to the individual person

Major Works:

Introduction to the Devout Life
Treatise on the Love of God
Numerous letters and spiritual conferences

Influenced: St. Jane Frances de Chantal, The Visitation Order, St. John Bosco
Major Opponents: Calvinist leaders and Protestant movements
Titles/Honors: Saint, Founder of Order of Visitation, Doctor of the Church
Canonized: Yes. 1665 by Pope Alexander VII
Summary: He was another champion of the Catholic Reformation and lead writers of spiritual mysticism for ordinary Christians. He emphasized that all should strive for holiness, not just clergy, monks, and nuns. He encouraged people to practice love, gentleness, and charity towards not only God, but also their neighbor. He made notable attempts to persuade and bring the Calvinist movement back to communion with the church. His theology is more focused on common lay people, and how they can practice spiritual devotion in everyday life (similar to Thomas a Kempes or Therese of Lisieux). His masterpiece work, Introduction to the Devout Life, is considered the ultimate guide for spiritual practice and helped earn him the title of Doctor of the Church.

Jakob Bohme

Theological Legacy: Philosopher of Christian Mysticism
Dates: 1575-1624
Location: Upper Lusatia, Holy Roman Empire (present day Germany)
Position: German Lutheran mystic, spiritual writer, theologian
Influenced by: Lutheran Christianity, Christian mysticism, Paraclesus
Key Concepts:

Direct experiential knowledge of God
The interplay of divine love and divine wrath
Spiritual rebirth and inner transformation
The cosmos as a revelation of God's nature
The fall and restoration of humanity
The "Ungrund" (the primoradial divine abyss beyond comprehension)
Christ as the center of cosmic and spiritual redemption

Major Works:

Aurora
The Three Principles of the Divine Essence
The Threefold Life of Man
The Forty Questions of the Soul
Mysterium Magnum
The Way of Christ

Influenced: German Pietism, Friedrich Schelling, GWF Hegel, William Blake, Samuel Taylor Coleridge, Emmanuel Swedenborg, Western mysticism
Major Opponents: Gregor Richter, Lutheran theologians
Titles/Honors: "Teutonic Theosopher"
Canonized: No.
Summary: He is considered one of the founding fathers of Christian spiritually and mysticism (alongside Meister Eckhart and Emanuel Swedenbourg). As a German Lutheran his concepts applied to all Christian theology, in regard to a spiritual system within the natural world. He wrote many works pertaining to God, creation, evil, redemption, the inner spiritual life, divine love, freedom, the cosmos, and human transformation. Perhaps some of his more radical controversial concepts was the notion of "Ungrund", an endless abyss of nothingness that existed before creation. He also saw hidden meaning in the cosmos as a revelation of God's own inner life and history. Despite his somewhat controversial concepts, he went on to inspire many great philosophers of the Enlightenment Age and is still seen as one of the most influential theologians of Christian mysticism.

Cornelius Jansen

Theological Legacy: Advocate of Predestination
Dates: 1585-1638
Location: Acquoy, Holland; Ypres, Flanders, Spanish Netherlands (modern Belgium)
Position: Catholic theologian, Bishop Ypres, Leader of Jansenism movement
Influenced by: Augustine of Hippo, Pelagianism
Key Concepts:

Human nature severely damaged by original sin
Necessity of divine grace for salvation
Effective grace
Predestination
Moral rigor and strict piety
Critique of Jesuit Order
Anti-Pelagianism

Major Works:

Augustinus

Influenced: The Jansenist movement, Blaise Pascal
Major Opponents: Jesuit Order, Pope Innocent X, Pope Clement XI
Titles/Honors: Founder of Jansenism
Canonized: No. Was condemned as a heretic
Summary: He was a firm believer in Augustinian's controversial concept of predestination, which supported the claim that humanity could only be saved thru the grace of God. This stance was considered a form of anti-Pelagianism which was against the church's teaching of free-will. This belief claimed that Original sin of Adam and Eve tarnished humanity, and they can only be saved thru divine grace. Jansen's views were seen as much more extreme form of Augustine's predestination, which completely eliminated humanity's choice to accept or reject God. His belief was that this choice was already determined by God (where some were saved while others were damned). This concept inspired the movement of Jansenism, which especially came at odds with the Jesuit Order and broke off from the Catholic Church. The movement spread across the lowlands and became a popular sect within the Protestant Reformation for a while until it was outlawed by the French monarchy in 1708. Nonetheless it is considered the foremost movement against free will and in support of predestination.

17th century- Enlightenment and Rationalism

Blaise Pascal

Theological Legacy: Philosopher of Rational Limits
Dates: 1623-1662
Location: Clermont-Ferrand, France
Position: Mathematician, physicist, philosopher, theologian
Influenced by: Etienne Pascal (his father and teacher), Rene Descartes, Evangelista Torricelli, Galileo Galilei, Augustine of Hippo, Jansenism
Key Concepts:

Pascal's Wager- Even though God's existence is inconclusive, it is best to chose faith since the payout is eternal life
The Limits of Reason- Human reason is valuable but insufficient for understanding God. Thus faith is required
The Heart has its reasons- God is known thru the heart and experience, not just scholastic learning
Human Misery and Greatness- Humans are burdened by sin but are also great due to their relationship with God
Original Sin- Humans are corrupted by sin, and need God's grace to guide them
Divine Grace- Salvation depends on God's grace rather than just human grace

Major Works:

Thoughts
Provincial Letters
Memorial

Influenced: Existentialist theory, Soren Kierkegaard
Major Opponents: Jesuit theologians, Pelagians
Titles/Honors: Apologist
Canonized: No.
Summary: He was one of the great polymaths of the Enlightenment Age with many theological concepts, deeply influenced by Augustine of Hippo and Janeism. He specialized in the field of existentialism, focusing on God's existence and his relationship with humans. His most famous concept is Pascal's Wager, which is one I have always believed in. The wager is is although God cannot be scientifical proven, it is better to choose faith over atheism, because at least with faith you get a chance at eternal life. He claimed that humans are in a constant tug-of-war with sin and greatness, seeking union with God. Although he was also a great scientist who preferred reason, he did ultimately accept that the truth could not be revealed thru reason, and thus faith must be required. Even though he was Jansenist, he fervently defended Christianity and had so many great theological concepts that pertain to all of Christianity.

Emmanuel Swedenborg

Theological Legacy: Visionary of the Spiritual World
Dates: 1688-1772
Location: Stockholm, Sweden
Position: Scientist, engineer, inventor, philosopher, mystic, Christian theologian
Influenced by: Lutheran Christianity, Enlightenment science, Isaac Newton
Key Concepts:

Correspondences: the natural world reflects spiritual realities
Heaven, Hell, and the Spirit world: spiritual realms of the afterlife
Spiritual interpretation of scripture (hidden knowledge beyond it's literal meaning)
Unity of God (Trinity within one divine person)
Divine Love and Wisdom
The New Church (Tied to the Second Coming of Christ)

Major Works:

Arcana Coelestia
Heaven and Hell
Divine Love and Wisdom
Divine Providence
Apocalypse Revealed
Conjugial Love
The Christian Religion

Influenced: Church of the New Jerusalem,
Major Opponents: Orthodox Lutheran theologians, Critics of mysticism
Canonized: No.
Summary: He is one of the most famous Christian theologians and mystics of the Englightenment Age. Although he was a Lutheran Christian his theology applied to all forms of Christianity with an emphasis on spiritual mysticism. He strongly believed in the spiritual world that existed within the natural world. This form of spirituality could be accessed thru gnostic studies as well as deep meditation. Swedenborg wrote extensively on the realms of heaven, hell, and a spiritual world which served as a form of intermediary purgatory. After his death, his concepts grew in popularity and established somewhat of a cultish following throughout northern Europe. The New Church of Jerusalem was established, centered on Swedeborgism theology. Although his concepts were deemed a bit on the radical heretical side, he inspired many writes and philosophers (such as Ralph Waldo Emerson) during the transcendent movement of the 1800s. He is one of the first theologians I studied and really took to his mystical approach of transcendentalism and the spiritual afterlife.

18th century- Natural Religion

Alphonsus Ligouri

Theological Legacy: Doctor of Moral Theology
Dates: 1696-1787
Location: Kingdom of Naples (modern day Italy)
Position: Catholic priest, founder of Redemptorists, Bishop of Sant'Agata de Goti, theologian
Influenced by: St. Francis de Sales
Key Concepts:

Moral theology based on mercy and pastoral care
Equiprobalisim (a method for resolving moral doubts)
Universal call to holiness
Devotion to the Eucharist and Blessed Virgin Mary
Evangelization of the poor and neglected

Major Works:

Moral Theology
The Glories of Mary
The Practice of the Love of Jesus Christ
Visits to the Blessed Sacrament
The Way of the Cross

Influenced: The Redemptorist Order
Major Opponents: Jansenism
Titles/Honors: Saint, Doctor of the Church, Founder of Redemptorists
Canonized: Yes. 1839 by Pope Gregory XVI
Summary: He was a very influential theologian from the 17th century who challenged the Jansenism extremist theology with a middle approach referred to as Equiprobalism. This sought to balance moral practice with a middle ground between extreme rigorism and laxism. This ideology in my opinion is what separates Catholics from most Protestants, a middle ground approach. Alphonsus also promoted the practice of charity as well as extra emphasis on the Eucharist and the Virgin Mary. He established a religious order known as the Redemptorists who specialized in evangelization as well as ministry and care for the poor. Thru his many theological concepts as well as his holy practices who was later honored as a Doctor of the Church.

Jonathan Edwards

Theological Legacy: Advocate of Christian Experience
Dates: 1703-1758
Location: Windsor, Connecticut
Position: Congregationalist pastor, theologian, philosopher, revivalist preacher
Influenced by: Augustine of Hippo, John Calvin, Puritan theology, John Locke, Isaac Newton
Key Concepts:

The Sovereignty of God
Religious Affections- Genuine Christianity consists of desires and holy love
Revival and Conversion- True revival is the work of the Holy Spirit
Original Sin
Freedom of the Will- Despite being enslaved by sin, humans can freely choose according to their desires
The Beauty of God
God's Glory as the Ultimate End

Major Works:

Religious Affections
Freedom of the Will
Original Sin
The End for Which God Created the World
The Life of David Brainerd
Sinners in the Hands of an Angry God

Influenced: The First Great Awakening, New England Theology, Modern Evangelicalism
Major Opponents: Arminian theology, Nominal Christianity
Titles/Honors: Founder of Edwardsen theology
Canonized: No.
Summary: He is regarded as America's Greatest Theologian and was one of the key leaders of the First Great Awakening of the 1730s-1740s (also known as the Evangelical Revival). Rooted in Congregationalist, Calvinist, and Puritan tradition, Edwards wrote and preached on many topics pertaining to the beauty and affection of God. He argued that true religion comes from the heart and spiritual experience. He emphasized the need for all Reformed Christians to seek revival thru the Holy Spirit, overcoming their original sin, and seeking the Glory of God as the Ultimate End. When one considers that America was founded mostly by pilgrims, Puritans, and reformed Christians it's fair to think it's greatest theologian would be a Protestant pastor.

John Wesley

Theological Legacy: Advocate of Christian Perfection
Dates: 1703-1791
Location: Lincolnshire, England
Position: Anglican priest, theologian, founder of the Methodist movement
Influenced by: Anglicanism, Holy Club at Oxford, Moravian Christians, Martin Luther, Thomas Kempis, Jeremy Taylor, William Law
Key Concepts:

Salvation by faith
Sanctification and holiness
Christian perfection
Arminian theology
Methodical discipleship

Major Works:

Sermons on Several Occasions
Explanatory notes upon the new Testament
Articles of Religion

Influenced: Methodism, Charles Wesley, Francis Asbury, Thomas Coke
Major Opponents: Calvinist theologians
Titles/Honors: Founder of Methodism
Canonized: No
Summary: He was a Protestant theologian who led a revival movement in England that became the birth of Methodism. He wrote and preached extensively with an emphasis of personal holiness, salvation thru faith, and living a perfect life in union with God. This movement aligned itself with the Dutch teachings of Jacobus Arminius (Arminian Theology) and came at odds with the church of Calvinism. The major difference was that Calvinism believed only some were chosen for salvation (predestination) while Wesley and Arminius believed God offered salvation to all. Another key feature of Methodism was the system of discipleship, where small groups established communities and support groups to share in their faith.

Georg Wilhelm Friedrich Hegel

Theological Legacy: Philosopher of Idealism
Dates: 1770-1831
Location: Stuggart, Wuttemberg (modern day Germany)
Position: German philosopher, founder of Absolute Idealism, Professor of Philosophy at University of Berlin
Influenced by: Immanuel Kant, Johann Gottlieb Fichte, Friedrich Schelling
Key Concepts:

Absolute Idealism
Dialectical development
Geist (Spirit or Mind)
Historical progress through reason
Recognition and self-consciousness
History as the unfolding of freedom
Unity of opposites through higher synthesis

Major Works:

Phenomoneology of Spirit
Science of Logic
Encyclopaedia of the Philosophical Sciences
Elements of the Philosophy of Right

Influenced: Karl Marx, Friedrich Engels, Soren Kierkegaard, British idealism, Existenialism
Major Opponents: Soren Kirekegaard, Arthur Schopenhauer
Titles/Honors: Founder of Absolute Idealism
Canonized: No
Summary: Hegel is considered one of the greatest German philosophers with also much theological concepts. He was raised in the Lutheran tradition and applied many of his religious beliefs into his overall philosophy. Some of his most famous concepts included God as an Absolute Spirit (Geist), who lives among reality, nature, culture, and human thought. He also promoted the role of human history as a reflection of the development of one's spirit. The Trinity he saw within everyone, where God the Father was oneself, Jesus the Son was God's self-expression, and the Holy Spirit was the reconciliation and unity of God. He also considered the Incarnation as a central part of Christianity, and that humanity must seek reconciliation for their sin. While he was mostly celebrated as a philosopher and founder of Absolute Idealism, his contributions to modern theology cannot be overlooked.

19th century- Modern Theology

John Henry Newman

Theological Legacy: Doctor of Doctrinal Development
Dates: 1801-1890
Location: Oxford, England
Position: Anglican priest, philosopher, Catholic priest, Oratorian
Influenced by: Athanasius and Augustine
Key Concepts:

Development of Doctrine
Assent and faith
Conscience as the aboriginal Vicar of Christ
Relationship of faith and reason
University education and liberal learning
The role of the laity in preserving tradition

Major Works:

An Essay on the Development of Christian Doctrine
Apologia Pro Vita Sua
The Idea of a University
An Essay in Aid of a Grammar of Assent

Influenced: Second Vatican Council, Joseph Ratzinger
Titles/Honors: Saint, Cardinal, Founder of English Oratory, Doctor of the Church
Canonized: Yes. 2019 by Pope Francis
Summary: He is considered one of the great modern doctors of the church, who actually converted from Anglicanism to Catholicism. He most famous theological concept was his development of doctrine, which claimed that Christianity doctrine can continue to grow, while still keeping the roots of the Apostolic tradition. This concept basically understood that society was constantly evolving and the church should also update and evolve with it. So this idea encouraged the church to allow evolution and updates to it's doctrine alongside modern society. This was especially put in practice at Vatican I and Vatican II which sought to modernize the church or as Pope John XXIII said to bring it up to date. John Newman also made great contributions to modern understanding of conscience, education, and the relationship of faith and church. It's quite refreshing to see someone turn back to the Catholic Church, as opposed to all those who sought to break away from it.

Pope Leo XIII

Theological Legacy: Leader of Neo-Thomism
Dates: 1810-1903
Location: Rome, Italy
Position: Pope of the Catholic Church (1878-1903)
Influenced by: St. Thomas Aquinas
Key Concepts:

Catholic Social Teaching
Dignity of labor
Rights and duties of workers and employers
Private property as a natural right
Rejection of both socialism and capitalism
Harmony between faith and reason
Revival of Thomism (Aquinas teachings)

Major Works:

Rerum Novarum (on capital and labor)
Aeterni Patris (promoting the teachings of Aquinas)
Providentissimus Desu (biblical studies)
86 encyclicals during his papacy

Influenced: Modern catholic doctrine
Major Opponents: Socialism, communism, capitalism
Titles/Honors: Pope, Vicar of Christ, "Social Pope"
Canonized: No.
Summary: He is considered the "pope of the workers" who argued on behalf of labor rights, while rejecting the economic systems of socialism, communism, and capitalism. The turn of the 20th century was a key time in economic politics, that saw the rise of Socialism and Communism standing up against the booming inequality of Capitalism. Pope Leo XIII led the churches response during this political tension, by finding a middle ground that defended workers' rights while still upholding the institutions of private property and free enterprise. He also sought to apply the teachings of Thomas Aquinas to more modern times and continue to reconcile social reason with the faith (a revival that some referred to as Neo-Thomism). While some saw his views as an afront to secularism, Pope Leo did not see this as intervening on government affairs, rather enforcing the church's teachings on moral rights no matter the public policy. He is considered one of the great modern theologians who made great strides to improve the political climate thru faith and reason.

Soren Kierkegaard

Theological Legacy- Pioneer of Christian Existentialism
Dates: 1813-1855
Location: Copenhagen, Denmark
Position: Danish philosopher, Lutheran theologian, Father of Existentialism
Influenced by: Socrates, Michael Kierkegaard
Key Concepts:

Subjectivity and truth
Individual existence and authenticity
Anxiety and despair
The leap of faith
The Single individual standing before God
Critique of Christendom (Practice of Christianity without genuine faith)
Stages of life: aesthetic, ethical, and religious existence

Major Works:

Either/Or
Fear and Trembling
Philosophical Fragments
The Concept of Anxiety
Concluding Unscientific Postscript
The Sickness Unto Death

Influenced: Existentialism, Martin Heidegger, Karl Jaspers, Jean-Paul Sartre
Major Opponents: GWF Hegel
Titles/Honors: Father of Existentialism
Canonized: No
Summary: He is considered one of the greatest Danish philosophers and Lutheran theologians who specialized in the field of existentialism (why do we exist). He expanded on Hegels concepts of existing within the universe as a whole, and focused more on the individual aspect. He considered emotions such as anxiety, fear, and despair as necessary experiences in finding faith. He accepted there was only so much philosophy and scientific reason could understand, and everything after that came thru faith in God. His philosophical theories on existentialism on to inspire many other scientific and psychological thinkers such as Karl Jaspers and Jean-Paul Sartre (even though he was an atheist).

Therese of Lisieux

Theological Legacy: Doctor of the Little Way
Dates: 1873-1897
Location: Lisieux, France
Position: Carmelite nun, mystic, spiritual writer
Influenced by: Caremlite spirituality, Teresa of Avila, John of the Cross, her parents (Saints Louis and Zelie Martin)
Key Concepts:

The Little Way (appreciation to God in all that you do)
Total trust in God's mercy
Holiness through ordinary daily actions done with love and devotion to God
Spiritual poverty and humility
Love as the heart of the Christian vocation
Endurance thru the Dark Night of the Soul (struggle or lack thereof faith)

Major Works:

Story of a Soul
Poems, Prayers, and Letters

Influenced: Modern Catholic spirituality, Pope John Paul II, Mother Teresa
Titles/Honors: Saint, Doctor of the Church, the Little Flower
Canonized: Yes. 1925 by Pope Pius XI
Summary: She was a Carmelite nun, who died at the young age of 19 due to tuberculosis, yet went on to win the hearts of many Christians. It was thru her "Little Way" approach that she rose to fame and prominence as the most unlikely of theologians. She explained this spiritual way of life in her writing "Story of a Soul" which emphasizes total trust in God. It's a way of embracing one's childhood in everyday life, and appreciate the little things or actions that we often take for granted, as a gift of God's love. This approach describes how ordinary activities, especially the burdensome tasks such as performing chores or dealing with difficult people can be seen as a way to show your humble love to God. Despite being blessed with faith, Therese of Lisieux also wrote about her experiences of the Night of Faith, where she struggled with her faith towards the end of her life due to her illness. She was not the only great saint to experience this conflict of faith as it happened to other great Christians such as John of the Cross, Teresa of Avila, Francis de Sales, and Mother Teresa of Calcutta. Nonetheless she emphasized an endurance to always stay the course and put total trust in God, even during these difficult times. While her theological concepts might not be as philosophical as Augustine or Thomas Aquinas, she lived a very holy life according to her minimalist, devout, and spiritual approach. After her death she was quickly canonized in 1925, and was then surprisingly declared a doctor of the church in 1997 by Pope John Paul II (she is one of 4 female doctors including Teresa of Avila, Catherina of Siena, and Hildegard of Bingen). Her legacy experienced one of the greatest booms of devotional following throughout the 1920s, celebrating her as the Little Flower.

Nikolai Berdyaev

Theological Legacy: Philosopher of Personalism
Dates: 1874-1948
Location: Obukhiv, Kyiv, Russian Empire (modern day Ukraine)
Position: Russian religious philosopher, theologian,
Influenced by: Fyodor Dostoevsky, Immanuel Kant, GWF Hegel, Arthur Schopenhaur, Karl Marx
Key Concepts:

Freedom as the fundamental reality of existence
Christian existentialism
Personalism (the value of the human person)
Creativity as participation in divine activity
Spiritual freedom over determinism
Critique of rationalism, materialism, and collectivism

Major Works:

The Meaning of Creativity
The Meaning of History
The Destiny of Man
Freedom and the Spirit
The Beginning and the End
Dostoevsky
Slavery and Freedom

Influenced: Christian existentialism, Religious personalism
Major Opponents: Marxism, Communism, Determinism
Titles/Honors: Founder of the Free Academy of Spiritual Culture
Canonized: No
Summary: He is considered one of the most important Russian theologians, who boldly stood up against Marxist and Communist ideals in favor of freedom. He was heavily influenced by the writing of Dostoevsky which helped him develop much of his Christian existential theology. He was a champion of the concept of personalism which put the individual person (and their spirit) more important than the national state (as was presented by Soviet propaganda). Berdyaev also strongly opposed the concept of determinism since it meant free will, creativity, responsibility, and moral discipline would become impossible. He takes this concept a step further with his most radical idea that Freedom is the source of reality where all personality comes from. The fact that he rejected many of his homeland's theories of materialism, rationalism, collectivism, and communism make him all the more courageous of a theologian.

20th century- Christian Renewal

J.I. Packer

Theological Legacy: Advocate of Knowing God
Dates: 1926-2020
Location: Gloucestershire, England; British Columbia, Canada
Position: Evangelical theologian
Influenced by: John Calvin, Richard Baxter, John Owen, John Bunyan, JC Ryle, CS Lewis, Puritan Tradition
Key Concepts:

Knowing God in a personal relationship
The authority and infallibility of the bible
Reformed theology (Calvinism)
God's sovereignty and human responsibility
Holiness and sanctification
Catechesis and Christian formation
The role of the Puritans in modern Christianity
Evangelical Anglicanism

Major Works:

Knowing God
Evangelism and the Sovereignty of God
Fundamentalism and the Word of God
Keep in Step with the Spirit
A Quest for Godliness
Concise Theology
Growing in Christ

Influenced: Modern evangelic theology, Carl Trueman
Major Opponents: Theological liberalism, Secularism
Canonized: No.
Summary: He is considered one of the most influential Evangelical theologians of the modern era. His most famous concept was from his book "Knowing God" which described that every Christian should seek their own personal relationship with God. He felt the path to salvation was not so much thru scholastic knowledge but thru prayer, personal devotion, and living a holy life thru God. He was influenced by the Calvanist and Puritan tradition with an emphasis on biblical authority and the sovereignty of God. He became one of the most respected evangelical leaders in North America leading somewhat of a Calvinist/Reformed revival in the 1970s-1990s.

Gabriel Marcel

Theological Legacy: Philosopher of Hope
Dates: 1889-1973
Location: Paris, France
Position: French philosopher, playwright, musician, theologian Christian existentialist
Influenced by: Henri Bergson, Soren Kierkegaard, Phenomenology, Martin Buber
Key Concepts:

Being vs Having (A rejection of materialism in favor for existentialism)
Mystery vs Problem (A problem is something that can be solved, where a mystery can never be solved)
Presence (To be available and open to other people
Creative Fidelity (Relationships can strengthen faith and meaning over time)
Hope (Spiritual commitment that transcends all things)
Participation (Humans roles as participants in reality, not just spectators)

Major Works:

Metaphysical Journal
Being and Having
Creative Fidelity
Man Against Mass Society
The Mystery of Being
Influenced: Paul Ricoeur, Christian existentialism, Personalism

Major Opponents: Jean-Paul Sartre's atheistic existentialism
Canonized: No
Summary: He was a French Christian and polymath who later converted to Catholicism where he made many contributions to Christian existentialist philosophy. He most famously opposed the great French philosopher Jean-Paul Sartre who believed in atheism, nihilism, absurdity, and radical freedom of existence. Marcel proposed an optimistic outlook that was centered around the mystery of faith. He believed existence was defined by relationship, fidelity, participation, love, suffering, death, and hope in God. Marcel claims it is best to participate in the mystery that is God which offers a transcendent hope. It's a much more positive outlook on existence than the alternative in my opinion.

Joseph Ratzinger (Pope Benedict)

Theological Legacy: Advocate of Faith and Reason
Dates: 1927-2022
Location: Bavaria, Germany
Position: Catholic theologian, Cardinal, Pope Benedict (2005-2013)
Influenced by: St. Augustine, St. Bonaventure, Henri de Lubac, Hans Urs von Balthasar, Romano Guardini, Pope John Paul II
Key Concepts:

Faith and Reason belong together
Hermeneutic of Continuity
God is Love
Christianity as an encounter with the Personhood of Christ (not just a religious system)
Defense of Christian traditional doctrine against relativism
Importance of liturgy, beauty, truth, and worship

Major Works:

Introduction to Christianity
The Spirit of the Liturgy
Jesus of Nazareth trilogy
Eschatology: Death and Eternal Life
The Ratzinger Report
Called to Communion
Catechism of the Catholic Church

Influenced: Vatican II
Major Opponents: Hans Kung
Titles/Honors: Pope
Canonized: Not Yet (But very likely in the near future)
Summary: He is regarded as the greatest Catholic theologian of the modern era and considered the chief architect of Vatican II and the Catechism of the Catholic Church (alongside Pope John Paul II). He championed many modern concepts seeking to bring the church up to date. This included a union of faith and reason, where you cannot have one without the other. He was also strongly against the ideal of Relativism where people held different perspectives on theological matters. Ratzinger was a very academic scholar who sought to preserve and honor the tradition of the apostolic church. While many saw Vatican II as a revolution of Catholic concepts, Ratzinger strongly claimed it was rather a retrieval of biblical concepts. He was no doubt a conservative thinker, but still saw great value in the development of the church tradition. He especially emphasized the positive relationship with God as the source of love, truth, goodness, and beauty. It's thru all his theological contributions that he became pope, and it won't surprise me if he becomes canonized and even declared a doctor of the church in the next hundred years.

Sunday, August 16, 2026

Most Influential Christian Theologians

No comments: