Theological Study: The Ecumenical Councils

As I studied Catholic theology and read thru the Catechism, the history-nerd in me thought it would be fun to track the evolution of this doctrine. As I've stated in numerous prior posts, the message of Jesus Christ in the Gospels was not cut-and-dry. It was filled with parables and mystery that needed major interpretation. The church as we know it did not just emerge out of tradition but rather thru structured doctrine. It has been doctored by the greatest philosophers and theologians to have ever lived (such as St. Augustine of Hippo and Thomas Aquinas). Throughout history these theological concepts have been fervently debated and have even caused schisms within the Catholic Church. The church doctrine has undergone much evolution throughout it's 2000 year history.  However it's central creed still falls in line with the Apostolic tradition and the Nicene Creed established in 325 AD.

The official Catholic doctrine and church laws were established over time thru many church councils and synods. These were basically an assembly of all the prominent leaders of the church (and the state leaders for most of it's early history). A major church council was usually convoked by emperors or bishops to address a certain matter of importance. Of these many church councils, there are 21 that are officially recognized by the Catholic Church as Ecumenical. These means they were worldwide gatherings, where the pope oversaw the council and the established decrees were officially approved. There have been many other historically important church councils that were only regional or were rejected by the Catholic Church. 

This evolution will show the development of some of the greatest mysteries in Catholic theology. Such as the Holy Trinity, the role of Mary, the nature of Christ, the Filioque, Iconoclasm, and the Transubstantiation. It also demonstrates the progression of canon laws throughout history pertaining to clergy discipline, church ecclesiastic structure, liturgical calendars, dealing with heresy, laity standards, and papal infallibility. Many of these debated topics caused major schisms in the Catholic Church. I'll later like to dive further into these topics of Christian theology as well as the branches of schematic churches (such as the Oriental Orthodox, Eastern Orthodox, and Protestant Churches). 

Of the many disagreements throughout these church councils, there were about 4 major issues that led to a complete separation and establishment of a new splintered Christian churches. The first major disagreement was over the nature of Christ (two natures divine-and-human vs one unified nature) which lead to the Chalcedon schism and development of Oriental Orthodox Church. Second major one was the Filioque issue (which stated the Holy Spirit proceeded from the father and the son, and not just the father). This lead to the Great Schism of 1054 and the development of the Eastern Orthodox. The third major issue that contributed to the orthodox schism was the central authority of the pope. The Protestant Reformation introduced concepts of Sola Fide and Sola Scriptura (Faith and Scripture alone), which was considered a total afront to the established body and administration of the Catholic Church.

Early Pre-Ecumenical Councils

Council of Jerusalem (48-50 AD)

• Location: Jerusalem, Israel
• 
  Convoked: Apostles and Early Church Fathers
  
• Attendance Count: 20-50 (approx)
• President: James the Just
• Key Participants: 
• Saint Peter, Saint John the Apostle, Saint Paul, James the Just, Saint Barnabas, other apostles
• Topics Discussed: 
• Whether Gentiles must follow Jewish Mosaic Law
• Should they be circumcised
• Should they follow Jewish rituals and feast days
• Should they follow Jewish dietary laws (clean vs unclean food)
• The basis of salvation: Law vs Grace
• The Identity and scope of the Catholic Church
• Declared Doctrine: 
• Circumcision is not required to become a Christian
• Gentile Christians are not bound to Jewish Law
• Salvation is thru the grace of the Lord Jesus Christ, not the Law
• God makes no distinction between Jew and Gentile
• The Catholic Church is open to all nations
• Summary: This was the first church council mentioned in the Acts of the Apostle attended by the main fathers of the church such as Peter, Paul, John, and James. The main topic of discussion was pertaining to the Gentiles and what degree of Jewish laws would be required to follow Christ. The key distinction here is most early Christians were of Jewish background however gentile converts were not. This began the discussion of how much Jewish tradition would become incorporated into the new Christian religion. It was basically the Catholic Church's first official cutting of the chord from the foundation of Judaism.

Council of Rome (155) 

• Location- Rome, Roman Empire
• Key Figures:
• Saint Polycarp of Smyrna- Quartodeciman
• Bishop Anicetus of Rome
• Topics: The date of Easter (Quartodeciman issue)- Passover Day or Sunday?
• Outcome: No formal ruling. Early divide with Rome and Asia Minor

Synods in Phrygia/Hierapolis/Anchialus (165-180)

• Location: Phrygia, Hierapolis, Anchialus- modern day Turkey and Bulgaria
• Key Figures:
• Apollinarius of Hierapolis
• Sotas- Bishop of Anchialus
• Topics: Montanism- Believed the Holy Spirit was still giving new revelations to prophets such as Montanus, Prisca, and Maximilla. Believed in strict moral discipline and that the end times were near.
• Outcome: Reviewed during several synods near Phrygia and Anchialus where the Montanism movement was strongest. It was widely examined by the church and officially declared as extremist and false prophecy. The movement was similar to modern Puritan movements, and eventually faded out by the 4th and 5th century.

Council of Rome (193)

• Key Figures: 
• Pope Victor I
• Polycrates of Ephesus
• Irenaeus of Lyons
• Topics: Easter question
• Outcome: No universal agreement, however general leaning towards Quartodeciman as a form of Judaizing the Christian religion.
• Council of Ephesus (193)
• Key Figures:
• Polycrates, bishop of Ephesus
• Topics: Easter controversy
• Outcome: Polycrates defended the Quartodeciman belief. Asia Minor firmly rejects Rome's demands

Councils of Arabia (246-247)

• Location: Bostra, Arabia Petraea (southern Syria)
  
• Key Figures:
• Beryllus of Bostra, bishop of Arabia
• Origen of Alexandria
• Topics: Christology, did Jesus exist prior to his earthly life? What happens to the soul after death?
• Outcome: Origen persuaded Beryllus of the eternal existence of Christ and his identity as the Son. They also affirmed that the soul continued to exist after death.

Synods of Antioch (264-269)

• Location: Antakya, Southern Turkey (near the Syrian border)
• Key Figures: 
• Paul of Samosata, Bishop of Antioch
• Theodotus of Caesarea
• Firmilian of Caesarea
• Malchion
• Topics: Christology- Controversial teachings of Paul of Samosata that Christ was a mere man who was not eternally divine
• Outcome: Paul of Samosata was declared as heretical. He was removed from his bishop post of Antioch. Paul however refused to step down and had to be forcefully moved by the Roman Emperor Aurelian. This debate on Christ's eternal role as the Logos, led into the debate against Arianism and the early development of the Trinity.

Council of Carthage (251)

• Location: Carthage (modern day Tunis, Tunisia)
• Key Figures:
• Cyprian, Bishop of Carthage
• Cornelius of Rome
• Topics: Novatus controversy- those who lapsed during persecutions
• Outcome: Lapsed can be forgiven and restored to the church. Penance based on level of lapse. Rejected Novatianism.

Council of Iconium (258)

• Location: Central Anatolia (modern day Turkey)
• Key Figures:
• Firmilian of Caesara (Cappadocia Eastern bishop)
• Cyprian of Carthage
• Pope Stephen I (Rome)
• Topics: Rebaptism controversary- Should people baptized by heretics (such as Montanists) be forced to baptize again when converting to the church?
• Outcome: Rebaptism is required for those baptized outside the church. Ongoing dispute and disagreement between Rome and East.

Council of Elvira (306)

• Location: Elvira, Hispania Baetica (modern day Granada, Spain)
• Key Figures:
• Hosius of Corduba
• Bishops of Spain
• Topics: How to handle Christians who had lapsed (denied the faith or worshiped pagan gods) during the Diocletian persecution (303-305).
• Outcome: Harsh ruling on those who had lapsed during Diocletian persecution depending on the level of apostasy. Also produced 81 strict canon rules on topics ranging from adultery, sexual immorality, clergy misconduct, discouraging images in church, and relations with pagans and Jews.

Council of North Africa (311)

• Location: Carthage (modern day Tunis, Tunisia)
• Key Figures:
• Mensurius of Carthage
• Caecilian- An example of a bishop who had lapsed during persecutions
• Secundus of Tigisis
• Donatus the Great- The church must be made up of true believers, not traitors who had lapsed their faith.
• Topics: The Donatist controversy- Can clergy members who had apostatized during persecutions still be valid church leaders?
• Outcome: Disagreement between factions lead to the Donatist schism. One of the first major Christian schisms.

Synod of Neo-Caesara (314)

• Location: Neo-Caesarea (modern day Niksar, Turkey)
• Key Figures:
• Bishops of Pontus
• Gregory Thaumaturgus the Wonderworker
• Topics: Church discipline and order
• Outcome: 15 canons dealing with clergy conduct, moral discipline, penance rules, church hierarchy, catechumens

Synod of Ancrya (314)

• Location: Ancrya (modern day Ankara, Turkey)
• Key Figures:
• Regional bishops of Galatia and Asia Minor
• Topics: Eastern focus on discipline, penance, and Christians who had lapsed during persecutions
• Outcome: 25 canons that established a penance system based on level of guilt. Also addressed clergy discipline, moral laws, church order, and marriage rules. It essentially allowed restoration to those who had lapsed after levels of penance.

Council of Arles (314)

• Location: Arles, France
• Key Figures:
• Emperor Constantine- convoked the council
• Caecilian of Carthage- bishop accused of apostasy by Donatists
• Donatist followers
• Topics: Donatist controversy and schism. Also discussed discipline rules and church unity
• Outcome: 22 canons regarding clergy conduct, church's role in warfare, standardizing church practice, and how to handle traitors. It basically aligned with the imperial rules by declaring that Christians should fulfil their civic duties, even if it meant serving in the military. Donatists continued to reject this decision leading to their schism. This was the first major council convoked by imperial influence, since Constantine had recently legalized Christianity. It set the stage for the Council of Nicaea.

Ecumenical Councils and synods

1. First Council of Nicaea (325)

• 
  Location: Nicaea, Roman Empire (present day Iznik, Turkey)
• Convoked: Emperor Constantine the Great
• Attendance Count: 318 (200 bishops)
  
• President: Hosius of Corduba
• Key Participants: 
• Hosius of Corduna
• Constantine the Great
• Alexander of Alexandria
• Athanasius (Key defender of the council)
• Arius (leader of Arianism that sparked the Trinity debate)
• Meletius of Lyccoplis (leader of the Melitians, Church of Martyrs. Rejected those who had lapsed during persecution)
• Eusebius of Caesara
• Eusebius of Nicodemia
• Topics Discusses:
• The nature of Christ (Fully divine or a created being)
• Dispute of Arianism (God and Jesus were not the same being)
• The relationship between God the Father and the Son
• Whether there was a time when the Son did not exist
• Establishing a date for Easter
• Ecclesiastic matters such as the clergy and church order
• Declared Doctrine:
• Jesus Christ is declared fully divine, begotten not made
• Jesus is of the same substance of God. Consubstantial with the father
• Jesus, the Son is eternal and was there at the beginning
• Condemnation of Arianism (Arius is declared a heretic and exiled)
• Confirmation of the unity of God the Father and Jesus the Son
• Outlawed self-castration which had become a practice of extreme ascetics
• Forgiveness of those who had lapsed during persecution (in opposition to the Melitians and Novatianists)
• Easter would be celebrated on Sundays not dependent on the Jewish Calendar
• Establishment of the Nicene Creed
• Established Canon Laws:
• Rome, Alexandria, and Antioch are declared primary patriarchate regions. Jerusalem is honorary one.
• Minimum term for catechumens wishing to be baptized
• Prohibition of chaste marriages, known as spiritual marriages or syneisktism
• Authority of bishops jurisdiction; bishops were to be ordained in the presence of three other bishops
• Clergy were not to administer church freely in other regions they were not assigned to
• Prohibition of usury among clergy (distribution of loans)
• Prohibition of kneeling on Sunday
• Sect Judgements:
• Melitians opposed forgiveness for those who lapsed during persecutions. The were considered schismatics capable to rejoin Catholic Church
• Novatianists claimed the church cannot forgive all sins (only God can). They were considered schismatics capable to rejoin Catholic Church
• Paulianists claimed Jesus only became divine thru God's power. They were declared outright heretics, capable of re-baptism.
• Arianism argued that Jesus was created by God and not his equal. It was declared outright heresy
• Summary: This is considered the first and most important of the Ecumenical councils. It essentially established the basis of the creed Catholics live by to this day. The main focus was the dispute of Arianism which claimed that Jesus was created by God and was not of divine nature. It's leader Arius famously claimed "there was a time where the Son was not". The counter however led by Athansius was that salvation requires Christ to be fully God. Therefore he must be eternal and begotten from God. This position became the early establishment of the Trinity which claimed that Jesus and God were one in the same. However it did not officially establish the Holy Spirit as part of the Trinity until the next Council. Another major decision the church made was establishing Easter on a Sunday and not to be celebrated on the same day as Passover (thus further distancing themselves from Jewish customs).

Council of Gangra (340s)

• Location: Gangra (modern day Cankiri, Turky)
• Key Figures:
• Eusebius of Nicomedia
• Regional bishops of Asia Minor
• Topics: Extreme asceticism and their beliefs
• Outcome: Condemned radical ascetic practices and affirmed that marriage is legitimate. Also regulated the practice of asceticism to be subordinate to Church authority

Council of Antioch (341)

• Location: Antioch (modern-day Antakya, Turkey)
• Key Figures:
• Eusebius of Nicomedia
• Emperor Constantius II
• Topics: Nature of Christ, adjustments to the Nicene Creed. Church discipline and governance
• Outcome: This was an Eastern Church council that produced a slightly edited version of the Nicene Creed that rejected Christ as of the same substance and leaned into Arian theology. Issued 25 canons on church structure. Attempted to compromise on the debate of Arianism vs the Trinity but ultimately did not resolve the issue and could be seen as early tension between the West Latin Church and the Eastern Church.

Council of Sardica (343)

• Location: Sardica (modern day Sofia, Bulgaria)
• Key Figures:
• Hosius of Cordoba
• Athanasius of Alexandria
• Eastern bishops
• Western bishops supported by Pope Julius I
• Roman Emperor Constans (West)
• Roman Emperor Constantius II (East)
• Topics: Arian Controversary. Church Unity between East and West
• Outcome: The council was split on the Arian debate of Christ's divine nature. West reaffirmed the Nicene Creed while the East continued to oppose it's wording.

Council of Rimini/Seleucia (359)

• Location: Rimini, Italy; Seleucia (modern day Turkey)
• Key Figures:
• Emperor Constantius II (Byzantine Emperor)
• Western bishops at Rimini (pro Nicence)
• Eastern bishops at Seleucia (
• Topics: The nature of Christ and his relation with the Father. The debate on the term homoousios "same substance" in the Nicene Creed.
• Outcome: Both west and east councils were pressured into accepting the Homoian creed which replaced the term "same substance" with "like the father". This was however a temporary compromise and would be revisited at the Council of Constantinople (381)

Council of Laodicea (363-364)

• Location: Laodicea in Phrygia (modern day Turkey)
• Key Figures:
• Regional bishops of Asia Minor
• Topics: Church discipline, proper worship practices, regulation of biblical readings, rejection of heretical groups (including Arians). Sabbath vs Sunday observance debate (honor Sunday vs strict Sabbath observance per Jewish tradition). Earliest discussion of biblical canon
• Outcome: Produced a series of canon rules on church liturgy, discipline, and structure. Reinforced Nicene concepts. Discouraged Jewish practice of Sabbath. Provided an early structure of the canonical books of the Bible. Discouraged Arianism, Montanism, Novatians, Donatists, and Christians Judaizers (who still kept Jewish law and traditions). Also condemned the worshiping of angels.

2. First Council of Constantinople (381)

• 
  Location: Constantinople, Roman Empire (modern day Istanbul, Turkey)
• Convoked: Emperor Theodosius I
• Attendance Count: 150
  
• President: Meletius of Antioch, Gregory of Nazianzus
• Key Participants:
• Timothy of Alexandria
• Meletius of Antioch
• Gregory of Nazianzus
• Nectarius of Constantinople
• Topics Discussed: 
• Further Dispute on Arianism
• Nature of the Holy Spirit
• Definition of the Trinity
• Church authority and order
• Ongoing Sect Disputes
• Declared Doctrine:
• Establishment of the Holy Trinity (Father, Son, and Holy Spirit as Co-equals)
• Holy Spirit declared as divine. The lord and giver of life who proceeds from the Father.
• Expansion of the Nicene Creed
• Established Canon Laws:Confirms the Bishop of Rome is leading bishop of the church.
• Bishop of Constantinople is secondary rank.
• Gregory of Nazianzus was declared legitimate bishop of Constantinople, while Maximus the Cynic was declared illegitimate
• Sect Judgements: 
• Macedonianism denied the divinity of the Holy Spirit. They were declared heretics.
• Apollinarians claimed that Jesus had a human body but a divine mind and spirit. They were declared heretics.
• Arianism was reaffirmed as heretics
• Summary: This was another very important early council of the church fathers that defined the Holy Spirit's divine role. The Nicene Creed was expanded to include this belief in the Holy Spirit as the giver of life who proceeds from the father. This also completely defined the Holy Trinity where God the Father, Jesus the son, and the Holy Spirit were all seen as the same God. It organized the bishop hierarchy with Rome as the central seat of power, and Constantinople in the second position of authority. The office of the pope was not officially declared yet. The council also continued their disputes with Arianism over the nature of Christ, standing by their original declaration that he was fully divine.

Synod of Hippo (393)

• Location: Hippo Regius (modern day Annaba, Algeria)
• Key Figures:
• Saint Augustine of Hippo
• Saint Aurelius, Bishop of Carthage
• Topics: Biblical canon
• Outcome: Produced one of the earliest lists of the canonical scripture books. This included the Jewish books of the Old Testament and the 27 apostolic books of the New Testament.

Council of Carthage (397)

• Location: Carthage (modern day Tunis, Tunisia)
• Key Figures:
• Saint Aurelius, Bishop of Carthage
• Saint Augustine of Hippo
• Topics: Biblical canon (Old and New Testament). Church discipline and administration.
• Outcome: Considered one of the most important non-Ecumenical councils. Officially selected the scriptural books that would make up the Catholic Bible as we know it today.

Council of Carthage (419)

• Location: Carthage (modern day Tunis, Tunisia)
• Key Figures:
• Saint Aurelius of Carthage
• Saint Augustine of Hippo
• Topics: Biblical canon
• Outcome: Reaffirmed the scriptural list that was established in the Council of Hippo (393) and Council of Carthage (397). Incorporated this list into a Code of Canons to be used throughout North Africa, and eventually into Rome.

3. First Council of Ephesus (431)

• 
  Location: Ephesus, Roman Empire (present day Selcuk, Turkey)
• Convoked: Emperor Theodosius II
• Attendance Count: 200-250
  
• President: Cyril of Alexandria
• Key Participants:
• Cyril of Alexandria (Defender of Theotokos- Mary as the "God-bearer")
• Nestorius (Defender of Christokos- Mary as the "Christ-bearer"
• John of Antioch
• Topics Discusses:
• Christology (The definition of Christ's divinity and humanity)
• Mary's official role
• Dispute the teachings of Nestorius
• Declared Doctrine:
• Mary is declared the Theotokos (Mother of God)
• Jesus Christ is one person (fully divine and fully human)
• Established Canon Laws:Reaffirmed the Nicene Creed as final
• Reinforcement of episcopal hierarchy and structure
• Sect Judgements: 
• Nestorians rejected the Theotokos and argued that Christ was two persons (God the Son and Jesus the Man). Declared as heresy.
• Aftermath:
• Nestorian Schism (1st major schism in the Catholic Church)
• Emergence of the Church of the East
• Summary: The major highlight at this council was declaring Mary the mother of God "Theotokos". This falls in line with the Trinity theory since Jesus was declared as the co-equal of God. Therefore she is proclaimed as not only the Christ-Bearer but also the God-Bearer. The second major development was the personification of Christ as one person (divine and human) and not as two separate persons. This is not quite the official Divine Incarnation yet which later established the two natures of Christ. The main opponent of this council was against the teachings of Nestorius the Patriarch of Constantinople. His claims were ultimately decreed as heretical and he was removed from his post. Worth noting John of Antioch arrived late to the council and ultimately disagreed with Cyril's ruling and felt the counsel was rushed. This council led to the first major schism where the Nestorians joined the Church of the East which was the chuch body outside the Roman Empire. The city of Seleucia-Ctesphion in Persia, was considered their Catholicos (patriarch headquarters) of the church.

Second Council of Ephesus (449)- Not recognized by Catholic Church

• Location: Ephesus, Roman Empire (present day Selcuk, Turkey)
• Convoked: Emperor Theodosius II
• Attendance Count: 127-135 Bishops
• President: Dioscorus of Alexandria
• Key Participants:
• Dioscorus of Alexandria
• Flavian of Constantinople
• Domnus II of Antioch
• Eutyches (Monk from Constantinople)
• Juvenal of Jerusalem
• Barsumas
• Topics Discussed:
• Christology (The nature of Christ)- one nature vs two natures
• Condemnation of Nestorianism
• Declared Doctrine:
• Accepted Eutyches' teachings of Monophysitism
• Sect Judgements: 
• Condemnation of Flavin's teachings (one person, two separate natures)- he was later physically assaulted and killed.
• Aftermath:
• This council was rejected by the Catholic Church
• This decision would essentially be completely reversed in the next council.
• Summary: This one was mostly a continuation on the debate of Christ's identity. Whereas the last council established he was one person with two natures, this council sought to further identify those natures. There was also still debate among those who supported Nestorianism (two-person theory). Eutyche was a prominent abbot from Constantinople who introduced new teachings that Christ had one nature (known as Monophysitism). This was against Flavian's teachings of the two-nature Christ. Eutyches' theory was generally accepted in this council with the strong backing of Dioscorus. The church thus accepted briefly that Christ had one nature, where the divine and human nature were merged into one. Flavian was later condemned and killed by the supporters of Eutyches. This council is often referred to as the Robber Council, as an abuse of authority by Dioscorus. It's doctrine was quickly rejected and reversed in the next council.

4. Council of Chalcedon (451)

• 
  Location: Chalcedon, Roman Empire (present day Kadikoy, Turkey)
• Convoked: Emperor Marcian
• Attendance Count: 500-600 bishops
  
• President: Anatloius of Constantinople with papal legates representing Pope Leo the Great
• Key Participants:
• Papal Legates
• Anatolius (Patriarch of Constantinople)
• Dioscorus of Alexandria
• Topics Discussed:
• Christology (Nature of Christ)
• Re-evaluation of Eutyche's doctrine
• Authority and hierarchy of bishops in Constantinople and Rome
• Declared Doctrine:
• Divine Incarnation (Jesus is one person with two natures; divine and human)
• Hypostatic Union Doctrine
• Established Canon Laws:Disciplinary actions on clergy rules and misconduct
• Constantinople is granted equal privileges as Rome
• Sect Judgements: 
• Eutyches (Monophystism) rejected and declared a heresy
• Dioscorus was excommunicated
• Flavian was posthumously vindicated, recognized as orthodox, and canonized as a saint and martyr
• Aftermath:
• The Chalcedon Schism breaks away from the Catholic Church
• Establishment of the Oriental Orthodox Churches
• Collapse of Alexandria and Antioch patriarchies
• Rome and Constantinople emerge as the new central powers of the Church (which began a new debate on centralized authority)
• Summary: This is one of the most important early church councils, that completed it's dogma on the Divine Incarnation. It basically reversed Eutyche's theory of monophysitism that claimed Christ had one nature, and defined that he had two natures (divine and human). This was in accordance with Flavius teachings and he was posthumously . Dioscorus of Alexandria was also put on trial for his abuse of power, and was excommunicated. This paved the way for the emergence of Pope Leo via his legates to assume power, and further divided the Eastern Church from the Roman Catholic Church. Those against the Chalcedon decrees of Christ's two natures were mostly situated in Alexandria, Syria, and Armenia which marked the emergence of the Oriental Orthodox Churches such as the Coptic, Syrian, and Armenian Apostolic Church. These churches rejected the definition of Christ as two natures and supported Cyril of Alexandria's theology that Christ had one united nature. This marked the rise of the Roman and Constantinople churches (under Pope Leo the Great) and the decline of the Alexandria and Antioch ones.

Third Council of Ephesus (475)- Not recognized by Catholic Church

• Location: Ephesus, Roman Empire (present day Selcuk, Turkey)
• Convoked: Emperor Basiliscus
• Attendance Count: 500-700 Bishops
• President: Timothy II Aelurus (Alexandria)
• Key Participants:
• Peter the Fuller (Patriarch of Antioch)
• Paul, Exarch of Ephesus
• Topics Discussed:
• Christology (Nature of Christ)
• Miaphysitism vs Chalcedonian Dyophysitism (one united nature vs two natures in one person)
• Legitamacy of Council of Chalcedon
• Church authority over Ephesus
• Aftermath:
• Catholic church completely rejected this council
• Chalcedon Schism and Oriental Orthodox Church continue to develop by the Miaphysites
• Summary: This council was organized by the growing faction of anti-Chalcedons Miaphysties who rejected the previous ruling on Christ's nature. This faction of Miaphysitism believe that Christ was one person with one united nature (divine and humany). They rejected Eutyche's school of Monophystism that believed Christ had one nature (that was more divine than human). Since Eutyches were previously declared heretics by the Council of Chalcedon this was mostly a dispute between Miaphysitism and the Chalcedonian Dyophysitism (one united nature vs two natures in one person). While it seems somewhat trivial and almost like the same thing, the key distinction was to acknowledge Christ's humanity as separate from his divinity and not to blend the two. This minor disagreement continued the Chalcedon Schism.

Council of Orange (529)

• Location: Orange, Gaul (modern day France)
• Key Figures: 
• Caesarius of Arles
• Gallic bishops from the Frankish Kingdom
• Topics: Grace and Free will. Original sin. Predestination (God determines who will be saved) . Semi-Pelagianism (Humans can grow their faith without God's grace).
• Outcome: Affirmed free will that begins with divine grace for salvation. Rejected semi-Pelagianism. Rejected predestination. This is basically stating that all Grace comes from God, and our free will chooses to accept or reject this grace.

5. Second Council of Constantinople (553)

• 
  Location: Constantinople, Roman Empire (modern day Istanbul, Turkey)
  
• Convoked: Emperor Justinian I
• Attendance Count: 150-160 bishops
• President: Patriarch Eutychius of Constantinople
• Key Participants: 
• Patriarch Eutychius
• Pope Vigilius
• Topics Discussed:
• Three Chapters Controversy (supporters of Nestorianism)
• Nestorianism (Christ as two persons; Divine and human)
• Origenism (Pre-existence, subordinationism, and salvation for all sinners)
• Evagrius (Asceticism, freedom from passions, purging evil thoughts)
• Declared Doctrine:
• Affirmed Christ is one person in two natures
• Sect Judgements: 
• Origenism considered heresy
• Rejected Nestorianism
• Condemnation of Evagrius teachings
• Summary: Held at the Hagia Sophia, this council attempted to bridge the divide between the Chalcedonians and the miaphysites by further rejecting Nestorianism (Christ as two persons). Emperor Justinian targeted three accepted church writings that upon further evaluation were considered favoring the heresy of Nestorianism. This included the writings of Theodore of Mopsuestria, Theodoret of Cyrrhus, and Ibas of Edessa. The teachings of Origen of Alexandria and Evagrius were also brought under review, which included theories on pre-existence (that souls existed before birth), salvation for all sinners, and the concept of subordinationism (in which Christ was subordinate to God). Despite it's attempt to find agreements with the Miaphysites, the council did not help bridge the Chalcedonian Schism since the disagreement of Crist's nature continued.

Council of Braga (561;572)

• Location: Braga (modern day Portugal)
• Key Figures: 
• Marin of Braga (Bishop of Braga)
• King Ariamir (561, Suebi Kingdom)
• King Miro (572, Suebi Kingdom)
• Topics: Priscillianism (a heretical movement that believed in dualism and extreme asceticism). Creation and the human body. Church discipline, organization, and liturgical practices.
• Outcome: Condemned Priscillianism as heresy. Affirmed that the creation and human body are good and rejected dualist theories that matter is evil. Standardized church structure in Spain and Portugal.

Council of Toledo (589)

• Location: Toledo, Visigothic Kingdom of Spain
• Key Figures:
• King Reccared I (Visigoth king who converted to Catholicism)
• Leander, bishop of Seville
• Topics: Conversion of Visigoths from Arian Christianity to Catholicism. Trinity vs Arianism. The clause of the Filioque stating that the Holy spirit proceeds from the Father and the Son.
• Outcome: Official conversion of the Visigothic Kingdom to Catholicism. Condemnation of Arianism. Formally included the Filioque in the Nicene Creed. This would later become a very contested topic with the Eastern Church.

Lateran Synod (649)

• Location: Rome, Italy (Lateran Palace)
• Key Figures: 
• Pope Martin I
• Maximus the Confessor
• Topics: Monothelitism (teaching that Christ has only one will). Nature of Christ's will.
• Outcome: Condemnation of Monothelitism. Affirmation that Christ has two wills. One that is divine. One that is human. The Byzantine emperor Constans II rejected this council since he supported Monothelitism and had both Pope Martin and Maximus the Confessor executed.

Synod of Whitby (664)

• Location: Whitby Abbey, Northumbria (modern day England)
• Key Figures:
• King Oswiu of Northumbria
• Abbess Hilda of Whitby
• Colam of Lindisfarne
• Wilfrid of York
• Agilbert
• Topics: Date of Easter. Tonsure (monastic hairstyles). Authority of Celtic Christianity and Roman Christianity. Whether English Church should follow Celtic tradition or Roman tradition?
• Outcome: King Oswiu chose to follow Roman tradition for England. The calculation of Easter was adopted. English Celtic clergy withdrew from the new Catholic Church in England and returned to Ireland.

Council of Hatfield (679)

• Location: Hatfield, England
• Key Figures: 
• Theodore of Tarsus (Archbishop of Canterbury)
• English bishops of the Anglo-Saxon church
• Topics: Monothelitism, Christology, Alignment of English church doctrine with the Roman Catholic doctrine
• Outcome: Rejected Monothelitism, affirmed that Christ has two wills. Strengthened unity between English Church and Roman Church

6. Third Council of Constantinople (680-681)

• 
  Location: Constantinople, Roman Empire (modern day Istanbul, Turkey)
• Convoked: Emperor Constantine IV
  
• Attendance Count: 300 bishops
• President: Patriarch George of Constantinople
• Key Participants:
• Patriarch George of Constantinople
• Patriarch Macarius of Antioch (opposed the council)
• Patriarch Sergius of Constantinople
• Papal legates of Pope Agatho
• Topics Discussed:
• Monothelitism (Christ had two natures, but one will)
• Monoenergism (Christ has two natures, but one energy)
• Relationship between Christ's will and nature
• Declared Doctrine:
• Christ had two wills just as he had two natures (divine and human)
• Sect Judgements: 
• Monothelitism (declared as heresy)
• Monoenergism (declared as heresy)
• Summary: This council dove deeper into Christology by defining his will and energy. The theory of Monothelitism stated that Christ had two natures but one will that was driving his actions. The church rejected this idea as counterintuitive, and declared that Christ had two wills that corresponded with his two natures of divine and human. The main argument from the Catholic Church was not to diminish Christ's humanity by an overpowering divine will. Thus it made since that he had two separate wills that came from his divine or human nature, that were both still aligned with one another. This ruling further divided the anti-Chalecedons who still felt Christ should have one single united nature and will.

Quinisext Council (692)

• Location: Constantinople, Byzantine Empire (modern day Turkey)
• Key Figures:
• Emperor Justinian II
• Patriarch Paul III of Constantinople
• Eastern Bishops
• No participation from Western Roman Bishops
• Topics: Church discipline, canon laws, monastic regulations, differences between Eastern and Western traditions
• Outcome: 102 canons on church discipline. The Catholic Church rejected most of this council except several moral laws and the shift away from depicting Christ as a lamb.

Council of Hieria (754)

• Location: Palace of Hieria, Byzantine Empire (modern day Turkey)
• Key Figures: 
• Emperor Constantine V
• Archbishop Theodosius of Ephesus
• 338 Eastern bishops.
• No participation from Western Roman Bishops
• Topics: Iconoclasm controversary against displaying religious images. Could Christ be depicted in an icon? Were these images considered a form of idolatry?
• Outcome: Condemned the veneration and use of icons. Declared the only true image of Christ is the Eucharist. Issued decrees against the creation and veneration of images. This ruling was not accepted by the Catholic Church even though it was a widespread sentiment. This Eastern ruling against icons was officially reversed at the Second Council of Nicaea in 787 which was approved by both East and West churches.

7. Second Council of Nicaea (787)

• 
  Location: Nicaea, Byzantine Empire (present day Iznik, Turkey)
  
• Convoked: Emperor Constantine IV and Empress Irene
• Attendance Count: 350 (300 bishops)
• President: Patriarch Tarasius of Constantinople
• Key Participants:
• Patriarch Tarasius
• Papal legates of Pope Adrian
• Topics Discussed:
• Iconoclast Controversy (destruction of images)
• Legitimacy of icons of God, Christ, Mary, Saints
• Distinction between Veneration and Worship
• Declared Doctrine:Icons are permitted, but should not be worshiped
• Veneration is an honor given to images
• Worship is adoration that belongs only to God
• Established Canon Laws:
• Proper use of icons in worship
• Regulation of church discipline and clergy conduct
• Sect Judgements: 
• Rejected Iconoclasm
• Summary: This Council was established as a response to the Iconoclast Controversy that had emerged from the Council of Hieria in 754 AD. This movement against the use of icons began in the Byzantine Empire during the early 700s. Emperor Leo III outright banned the use of icons from 726-730. These forms of visual representation of God, Jesus, Mary, or the saints (paintings or statues) were seen as a form of idolatry. Much of this was influenced by the growing presence of Islam, who firmly rejected any form of icons in worship. Many Romans however rejected this stance and supported the use of Icons since God himself became visible thru the Divine Incarnation. They went a step further by clarifying the importance between veneration and worship. Veneration was a form of respect and honor that could be bestowed upon Mary, the saints, and holy images, while only God could be fully worshiped. This way they ruled out any practice of idolatry or polytheism by allowing holy images, statues, churches, or relics to be venerated. This also went for the many holy figures that fall below the Godhead, such as Mary, the angels, and the saints. These holy figures were to be honored and respected while only God was to be worshiped. This debate went on for another 50 years and icons were not completely permitted until 843.

Council of Frankfort (794)

• Location: Frankfort, Frankish Empire (modern day Germany)
• Key Figures: 
• Charlemagne (convoked the council)
• Pope Hadrian's legates
• Paulinus of Aquileia
• Alcuin of York
• Numerous bishops from Gaul, Italy, Aquitaine, and England
• Topics: Adoptionism (Christ was born human and then adopted by God as divine). Iconoclasm. Church discipline, governance, and monastic rules
• Outcome: Issued 56 canons on church laws. Condemned Adoptionism as heresy. Rejected parts of the Second Council of Nicaea that allowed the veneration of icons. This council declared that images could be allowed but should not be venerated. This was mostly a temporary local disagreement and the Catholic Church continued with the 787 ruling of Nicaea II, which allowed the veneration of icons, as long as they were not worshiped.
  

Synods of Aachen (816-819)

• Location: Aechen, Frankish Empire (modern day Germany)
• Key Figures:
• Emperor Louis the Pious
• Benedict of Aniane
• Frankish bishops and abbots
• Topics: Monastic reform, Rule of St. Benedict (monastic rules), distinction between monks and clergy.
• Outcome: Rule of Benedict was confirmed as the standard rules for all monasteries. More structured communal clergy life. Strengthened church unity and discipline. Aligned it's organization to have close ties with the Carolingian Empire.

Synod of Constantinople (843)

• Location: Constantinople, Byzantine Empire (modern day Istanbul, Turkey)
• Key Figures:
• Empress Theodora
• Emperor Michael III
• Patriarch Methodios I of Constantinople
• Topics: 2nd wave of Iconoclasm controversary. Veneration of Icons.
• Outcome: Restored the use and veneration of icons in the Byzantine Church. This was the final resolution of the Iconoclast Controversary that reaffirmed the rulings of the Second Nicaea Council. Established the annual feast, "Triumph of Orthodoxy" still celebrated today in the Eastern Orthodox Church.

Photian Synods (867; 879-880)

• Location: Constantinople, Byzantine Empire (modern day Istanbul, Turkey)
• Key Figures:
• Photius- Patriarch of Constantinople
• Emperor Michael III (867 synod)
• Emperor Basil (879-880 synod)
• Pope Nicholas I
• Pope John VIII
• Patriarch Ignatius
• Topics: Authority of the church (papal supremacy vs patriarchal independence). Could the pope intervene on Constantinople bishop appointments? Filioque controversary. Jurisdiction debate.
• Outcome: Condemnation of papal authority and the filioque clause. Temporary Compromise but was the beginning of the break-up between East and West that lead to the Great Schism of 1054.

8. Fourth Council of Constantinople (869-870)

• 
  Location: Constantinople, Byzantine Empire (modern day Istanbul, Turkey)
• Convoked: Emperor Basil I, Pope Adrian II
  
• Attendance Count: 102 bishops
• President: Emperor Basil I
• Key Participants:
• Emperor Basil I
• Patriarch Ignatius of Constantinople
• Photius
• Papal legates of Adrian II
• Topics Discussed:
• Photian Schism (Dispute between Rome and Constantinople)
• Papal authority vs imperial authority
• Papal jurisdiction over Eastern churches
• Declared Doctrine:
• Reaffirmed veneration of icons
• Established Canon Laws: 27
• Sect Judgements: 
• Condemnation of Photius
• Ignatius of Constantinople reinstated
• Aftermath: 
• Byzantine eastern church leaders reject this ruling and call a counter-council ten years later
• Growing tension between Rome and Constantinople over papal authority in Rome
• Final Council involving East and West churches
• Great Schism of 1054
• Summary: This council was called primarily to resolve a growing dispute between the two major church capitals of Rome and Constantinople. The key issue was who had the authority to appoint and remove a patriarch of Constantinople. This issue came to the forefront when the Byzantine emperor removed the sitting patriarch of Constantinople Ignatius in place of Photius. Ignatius claimed this was an unlawful disposition by imperial forces which challenged the papal authority of Rome. Photius retorted that Rome did not have supreme authority of Constantinople, since according to canon law they were co-equals. This is where the convergence of power began to split, as Rome had seen itself as the seat of the pope, succeeded from Peter, and thus the supreme authority. Emperor Basil eventually accepted the church's ruling on the matter that the empire should not intervene on papal matters. However a few years later, after the death of Ignatius, a counter-council was called by prominent Byzantine leaders to reject this Fourth Council and reinstate Photius as patriarch of Constantinople. This was the beginning of the schism between the Roman church and the eastern orthodox church. It was also the last time both sides would officially meet together in the same council. The Schism of 1054 officially divided Rome and Constantinople over this dispute of papal authority. The final straw for the east came when the Roman Church added the Filioque to the creed in 1014 without eastern approval (which stated the Holy Spirit proceeded from the Father AND the son). The East disagreed with this wording since it made it sound like God and Jesus were the source, when it should only be God. The bigger problem was not so much the wording, however the fact that Rome was now acting on it's own accord without eastern council.

Synod of Sutri (1046)

• Location: Sutri, Italy
• Key Figures:
• Emperor Henry III (Holy Roman Emperor)
• Pope Gregory VI
• Pope Benedict IX
• Antipope Sylvester III
• Roman clergy and bishops
• Topics: The papal crisis of three rival popes at the same time. Reform the papacy election process and remove corruption and factional division.
• Outcome: All three antipopes were deposed and replaced by one pope, Clement II. This marked a major intervention by imperial authority into church matters. This later set the stage for the Investiture Controversy, a dispute of authority between the church and the empire.

Synod of Vercelli (1050)

• Location: Vercelli, Italy
• Key Figures:
• Pope Leo IX
• Berengar of Tours
• Hildebrand (papal legate)
• Topics: The nature of the Eucharist and Christ's presence as the body and blood. (Was it symbolic or was it a physical transformation known as transubstantiation?)
• Outcome: Rejected Berengar's teachings that it was only a spiritual or symbolic presence. Affirmed the doctrine that Christ was physically present in the bread and wine as his body and blood.

Lateran Synods (1059, 1075, 1078)

• Location: Lateran Place (Rome, Italy)
• Key Figures:
• Pope Nicholas II (1059 Synod)
• Pope Gregory VII (1075, 1078 Synod)
• Topics: Church reform. Investiture Controversary. Church authority vs secular authority.
• Outcome: Condemnation of imperial influence on papal affairs, during the Investiture Controversary. Gave cardinals the decisive role in papal elections. Bans on simony, clerical marriage and disciplinary measures. Centralization of papal authority

Council of Clermont (1095)

• Location: Clermont, France
• Key Figures: 
• Pope Urban II
• Alexios I Komnenos (Byzantine Empire)
• Fulcher of Chartres (priest, historian)
• Robert the Monk (French prior)
• Baldric of Dol (archbishop)
• Guibert de Nogent (historian)
• Topics: Protection of Eastern Christians against Seljuk Turks. Recovery of Jerusalem and the Holy Land. Promotion of Pilgrimage and a Holy War
• Outcome: Launch of the First Crusade (1096-1099). Holy War under papal authority. Improved relations with West and Eastern Church against Islams
  

9. First Council of the Lateran (1123)

• 
  Location: Lateran Palace, Rome, Italy
  
• Convoked: Pope Callixtus II
• Attendance Count: 1000 (300 bishops, 600 abotts, 100 clergy)
• President: Pope Callixtus II
• Key Participants: Pope Callixtus II
• Topics Discussed:
• Investiture Controversary (dispute between church and state on appointing bishops)
• Clergy reform and discipline
• Established Canon Laws: 22
• Concordat of Worms
• Condemnation of simon (buying/selling church offices)
• Prohibition of lay investiture (lay rulers appointing bishops)
• Enforcement of clerical celibaby
• Protection of church property
• Safety for pilgrims and crusaders
• Summary: This was the first major Catholic Ecumenical Council without the Eastern Orthodox Church. It pertained to the Investiture Controversary primarily targeted at the Holy Roman Empire's involvement in appointing bishops. This was the conclusion of a famous 50-year standoff between Pope Gregory VII and Holy Roman Emperor Henry IV from 1076-1122. During the dispute Henry IV was forced by his own advisors to make a walk of atonement known as the Road to Canossa, so as to make peace with the church. The Concordat of Worms was officially drafted and declared at this council, which confirmed the church's authority was to be free from secular rulers. The council also passed many new strict canon laws to enforce this policy and deter any corruption and bribery from within their own clergy.     

10. Second Council of the Lateran (1139)

• 
  Location: Lateran Palace, Rome, Italy
  
• Convoked: Pope Innocent II
• Attendance Count: 500-1000 bishops and clergy
• President: Pope Innocent II
• Key Participants:
• Pope Innocent II
• St. Bernard of Clairvaux
• Topics Discussed:
• Papal Schism of 1130-1138
• Reform of clergy discipline and morality
• Condemnation of heretical movements
• Established Canon Laws: 30
• Clerical celibacy strictly enforced
• Condemnation of concubines or mistresses of clergy
• Regulation of clerical dress and behavior
• Enforcement of tithes (one-tenth paid contribution to church)
• Truce of God (limits on warfare)
• Prohibition of dangerous tournaments/jousts
• Sect Judgements:
•  Condemnation of Antipope Anacletus II
• Excommunication King Roger II of Sicily for supporting the schism
• Petrobrusians declared as heretics (Peter of Bruys sect that was seen as anti-sacramental and anti-institutional)
• Henricians declared as heretics (Henry of Lausanne sect encouraged self-penance verse institutional structure)
• Summary: This one focused on the aftermath of the papal schism caused by Antipope Anacletus II from 1130-1138. The contention began after the death of Pope Honorius II in 1130, where both Pope Innocent II and Anacletus II felt they had won the election. The confusion was due to recent election reform as well as political influence. Anacletus had won the majority vote, however Ignatius won via the new reformed process of authorized cardinals. So both had claims however Ignatius was the more in the right legally. Ignatius quickly gathered support from St. Bernard of Clairvaux and other prominent Western rulers which recognized him as the true pope and Anacletus as the antipope. The schism lasted for eight years where both men declared themselves pope until the death of Anacletius II. Following his death, there was major clean-up required to remove most of his appointments and re-unite the church. It also enforced many more new clerical laws pertaining to discipline and correction.

Council of Tours (1163)

• Location: Tours, France
• Key Figures:
• Pope Alexander III
• Topics: Church discipline and reform, heresy cases, clerical standards and conduct, separation of church and state
• Outcome: Stronger opposition against heresy. Strengthened papal authority and clerical discipline. Religious unity throughout Western Europe

Council of Lombers (1165)

• Location: Lombers, France (southern France)
• Key Figures: 
• Local catholic bishops
• Cathar representatives
• Topics: Catharism. Debate and examination between Catholic doctrine and dualist theology (two sources of good and evil).
• Outcome: Cathars were condemned as heresy. Rejection of dualist theory. Stronger anti-heresy campaigns. Laid groundwork for Albigensian Crusade (1209-1229)

11. Third Council of the Lateran (1179)

• 
  Location: Lateran Palace, Rome, Italy
  
• Convoked: Pope Alexander III
• Attendance Count: 1000 (300 bishops)
• President: Pope Alexander III
• Key Participants: Pope Alexander III
• Topics Discussed:
• Papal Schism of 1159-1178
• Reform of papal elections
• Church discipline and moral reform
• Condemnation of heretical movements (Cathars, Waldensians)
• Tension between pope and Holy Roman Empire
• Established Canon Laws: 27
• Papal election reform- only cardinals can elect pope with two-thirds majority
• Condemnation of simony and corruption
• Clerical discipline
• Education reform
• Age minimums for clergy
• Sect Judgements:
• Catharism declared as heretics
• Waldensians declared as heretics
• Summary: This council was established to once again sort out another papal schism that occurred from voting discrepancies. After a string of several antipopes, and restored peace between the papacy and the Holy Roman Empire, the council made it their primary effort to solidify the election process. The primary reform was that only cardinals could vote with a two-thirds majority (this format is still in place today). The council also continued to tighten it's ecclesiastic policies on clergy discipline. It also continued it's assessment of heretical movements, this time targeted at Catharism and Waldensians which had emerged from Crusader states. The council encouraged state leaders to enforce against heresy by any means necessary.

Council of Verona (1184)

• Location: Verona, Italy
• Key Figures:
• Pope Lucius III
• Emperor Frederick I Barbarossa
• Topics: Condemnation of Heresy (Cathars, Waldensians, Humilati). Strengthen cooperation between church and state.
• Outcome: Ad abolendam (anti-heresy laws). Ordered bishops and states to actively investigate and suppress heretical groups. Early development of Inquisition.

12. Fourth Council of the Lateran (1215)

• 
  Location: Lateran Palace, Rome, Italy
• Convoked: Pope Innocent III
  
• Attendance Count: 2000 (400 bishops, 800 abbots)
• President: Pope Innocent III
• Key Participants:
• Pope Innocent III
• Envoys from Frederick II
• St. Dominic
• St. Francis of Assisi
• Topics Discussed:
• Church reform and discipline
• Crusading efforts
• Heresy suppression of Cathars and Waldensians
• Role of Laity and Sacraments
• Declared Doctrine:
• Transubstantiation (Bread and wine become Body and Blood of Christ)
• Established Canon Laws: 71
• Annual confession and communion (especially at Easter)
• Procedures to enforce against heresy
• Clergy reform and education
• Marriage laws
• Social regulations on Jews and Muslims
• The call for a new crusade
• Sect Judgements:
• Further condemnation of Cathars and Waldensians
• Joachim of Fiore declared heretic
• Amaury of Bene declared heretic
• Aftermath:
• Fifth Crusade is launched from 1217-1221 and ends in yet another defeat for the Christian Crusader alliance
• Summary: One of the most important medieval councils that clearly defined major doctrine and church laws. It's famous for it's 70 canon laws pertaining to church structure and practice, but mostly for it's new doctrine of the transubstantiation. This officially declared that the presence of Christ was in the Eucharist, in which the holy spirit transformed the bread and wine into his body and blood. This is a tremendous miracle that occurs during mass, and is why the Eucharist is considered the most important sacrament in the church. The church also established new stricter rules on the laypeople, to receive communion and confession at least once a year. It was also very strict on Jews and Muslims, thus emphasizing the church's state of religious war at the time. This intention was made clear with their preparations for another crusade into Israel against the Muslims, which would become the Fifth Crusade. This council was seen as the height of the papal power during the middle ages.

Synod of Oxford (1222)

• Location: Oxford, England
• Key Figures: 
• Stephen Langton (Archbishop of Canterbury)
• English bishops and clergy
• Topics: Condemnation of heresy. Church discipline and clerical standards. Sacraments and parish life. Jewish-Christian relations.
• Outcome: Canon laws for church administration in England. Clerical discipline. Anti-heresy measures.

Council of Toulouse (1229)

• Location: Toulouse, France
• Key Figures:
• Folquet de Marselha (Bishop of Toulouse)
• Papal legates
• Topics: Catharism. Enforcement of inquisition post Albigensian Crusade.
• Outcome: Strengthening of the Medieval Inquisition. Restricted the bible from common folk. Strengthened church authority in France and across western Europe.

Synods of Beziers and Narbonne (1227, 1243, 1259) 

• Location: Beziers and Narbonne, France
• Key Figures:Pierre Amiel, Archbishop of Narbonne (1227)
• Papal legates
• Topics: Suppression of heresy (Cathars and Waldensians). Further development of Inquisition. Restrictions on Jews.
• Outcome: Passed strict anti-heresy laws, and methods of identification and surveillance. Established penalties for heretics. Strengthened church enforcement and authority.

13. First Council of Lyon (1245)

• Location: Lyon, France
• 
  Convoked: Pope Innocent IV
  
• Attendance Count: 250
• President: Pope Innocent IV
• Key Participants:
• Pope Innocent IV
• Baldwin II (Latin Emperor)
• Raymond VII of Toulouse
• Raymond Berenguer IV of Provence
• Topics Discussed:
• Conflict between papacy and Emperor Frederick II
• Clerical disicipline and reform
• The Crusades (preparation for the Seventh Crusade)
• The Gerat Schism
• Threats from Tatars/Mongols and Muslims
• Established Canon Laws: 38Church legal and judicial procedures
• Excommunication regulations
• Church financial administration
• Support for Latin Empire and Crusades
• Sect Judgements: 
• Excommunication of Emperor Frederick II
• Deposition of King Sancho II of Portugal
• Aftermath:
• Frederick rejected the council, and no peace was ever settled
• Summary: This council was another major standoff between the papacy and the Holy Roman Empire, this time Frederick II being the main culprit. The church felt he had been abusing his power on a number of issues, and ruled with total independence from the church. He controlled much of northern Italy and Sicily, and as the tension escalated Frederick decided to invade the Papal States during the War of the Keys (1228-1230). Pope Innocent IV tried to negotiate with Frederick, but as the war intensified he had no choice but to flee Rome and find refuge in Lyon. While in Lyon he made his case at this council to have Frederick II excommunicated for disobeying the church and endangering Christendom. Despite this act, the church was unable to resolve the tension with the Holy Roman Empire the way it had before during the Investiture Controversary. Both parties continued to undermine one another until the death of Frederick II in 1250. This marked a period of instability in the Holy Roman Empire known as the Great Interregnum but also demonstrated the limits of papal power over kings. The council also established many new procedural rules and emphasized the threat of the Great Schism divide, as well as the Tatars, Mongols, and Muslims.

14. Second Council of Lyon (1274)

• Location: Lyon, France
• 
  Convoked: Pope Gregory X
• Attendance Count: 300-500 bishops
  
• President: Pope Gregory X
• Key Participants:
• Pope Gregory X
• King James of Aragon
• Delegates from France, England, Germany, Sicily, Byzantine Empire, and Mongol Khan
• St. Bonaventure
• St. Thomas Aquinas (was invited but died en route)
• Topics Discussed:
• Reunion of Eastern and Western Churches
• The Crusades
• Church reform and discipline
• Papal elections
• Declared Doctrine:
• Eastern delegates accepted papal primacy and the Filioque clause (temporary union)
• Established Canon Laws: 31
• Establishing papal conclave system
• Regulations on clergy discipline, elections, and church property
• Financial measures (related to the Crusades)
• Sect Judgements:
•  Temporary reconciliation with Eastern Church
• Council recognizes Rudolf I as Holy Roman Empire, ending their interregnum
• Aftermath:
• This union was rejected and reversed ten years later after the death of Byzantine emperor Michael VIII Palaiologos in 1282
• Summary: This was another major effort by the Church to end the Great Schism and reunite the Western and Eastern churches. The timing of this council was mostly political, as the Byzantine emperor Michael VIII felt threatened by Balkan and Turkish invasions and needed western support. There was also fear that the West might invade the East outright as they did during the fourth crusade where they sacked Constantinople in 1204. Michael VIII therefore sent his Greek delegates to formally accept the two dividing factors; papal primacy and the Filioque. While this created an official reunion with the east and west, it was very unpopular in the eastern church. The majority of the eastern orthodox leaders rejected this council, and ten years later after the death of Michael VIII the decision was officially reversed by Andronikos II Palaiologos. The most notable impact from this council came with it's reform on church laws and papal elections. This introduced the process of conclave where cardinals would be locked in together to expedite their decision.

Council of Mende (1281)

• Location: Mende (France)
• Key Figures:
• Bishops of Languedoc
• Papal legates
• Topics: Suppression of heresy. Enforcement of Inquisition. Church discipline. Strengthening episcopal authority.
• Outcome: Reaffirmed earlier anti-heresy laws passed in Councils of Toulouse and Narbonne. Strengthened the role and authority of the Inquisition.

15. Council of Vienne (1311-1312)

• Location: Vienne, France
• 
  Convoked: Pope Clement V
• Attendance Count: 150-200 (120 bishops)
  
• President: Pope Clement V
• Key Participants:
• Pope Clement V
• King Philip IV of France
• Topics Discussed:
• The Knights Templar
• Reform of the church and clergy discipline
• Crusades and the Holy Land
• Disputes with Franciscan Order
• Concerns with Beguines and Beghards (lay people performing religious duties without vows)
• Established Canon Laws: 10
• Clerical morality
• Ecclesiastical discipline and governance
• Establishment of university chairs for missionary and scholarly pursuits
• Funding for another crusade
• Sect Judgements: 
• Order of the Knights Templar is dissolved
• Beguines and Beghards are declared heretical
• Summary: During this time the papacy had relocated from Rome to Avignon and was heavily influenced by the French king (1309-1377). The main matter on the table of this council was the disbandment of the Knights Templar. This is considered one of the more corrupt cases in the church's history that was influenced mostly by King Philip IV of France. His reasoning for dissolving the order was since he owed them money and they had amassed too much power in France. King Philip IV systematically accused them of heresy and coerced the pope into having them dissolved. Although the council did not have any reliable evidence against the Knights Templer, they were pressured into suppressing the crusader order. All their wealth was transferred to the Knights Hospitaller, and many of it's members were imprisoned and even executed. This is one of the first major examples of the shift-in-power, where the pope had now become dependent and influenced by the secular rulers. The church also came down heavily on beguines and beghards who were practicing religious devotions without any official vows. This was seen by the church as a dangerous form of heresy which lead to free-spirit teachings of Pantheism and perfectionism that were not aligned with church canon.

Council of Pisa (1409)

• Location: Pisa, Italy
• Key Figures: 
• Cardinals from Roman and Avignon factions
• Pope Gregory XII (Roman Claimant)
• Antipope Benedict XIII (Avignon Claimant)
• Antipope Alexander V (elected at council)
• Topics: The Rival pope dispute between Avignon and Rome. Conciliarism. Church unity and reform.
• Outcome: Instead of resolving the two-pope issue, it worsened it by creating three popes. This council was later rejected by the Catholic Church.

16. Council of Constance (1414-1418)

• 
  Location: Constance, Holy Roman Empire (modern Germany)
• Convoked: Emperor Sigismund and Antipope John XXIII
• Attendance Count: 600
• President: Giovanni Dominici and Carlo Malatesta
• Key Participants:
  
•  Emperor Sigismund (Holy Roman Empire)
• Antipope John XXIII
• Papal legates of Pope Gregory XII
• Jean Gerson
• Pierre d'Ailly
• Jan Hus (on trial)
• Followers of John Wycliffe (on trial)
• Topics Discussed:
• Western Schism (Rome and Avignon papacy)
• Heresies of Jan Hus and John Wycliffe
• Reform of the Church
• Conciliarism (Authority of councils vs pope)
• Just war theory (Poland-Teutonic Knights dispute)
• Declared Doctrine:
• Haec Sancta- Declared that a general council derives authority from God, and even the pope must obey it
• Established Canon Laws:
• Haec Sancta
• Frequens- Regular councils every 10 years
• Procedures for Papal election
• Reforms of Church governance
• Anti-heresy laws
• Sect Judgements: 
• Jan Hus declared a heretic and executed
• John Wycliffe declared a heretic and is posthumously condemned
• Antipope John XXII deposed
• Benedict XIII deposed
• Aftermath:
• The Hussite Wars (response to the execution of their leader led to a series of Civil Wars in Bohemia)
• Hus inspires reformers against the church corruption, that would lead the Protestant Reformation 100 years later
• Pope Martin V did not fully accept Haec Sancta where the council was superior to his authority
• Summary: This was a very productive council that achieved a lot of historical matters. First-and-foremast they ended the Western Schism between Rome and Avignon where a string of antipopes had challenged the authority of Rome. The previous Council of Pisa in 1409 attempted to fix this issue, but ultimately was rejected and created a third pope. The schism ended when Martin V was elected to restore unity in Rome. The council also famously summoned Jan Hus who was promised safe conduct by Emperor Sigismund. Upon his arrival he was arrested and tried as a heretic. The council gave him a chance to recant, but when he refused he was burned at the stake. The council also declared John Wycliffe a heretic, and had his dead corpse exhumed and burnt. They established a new hierarchal structure granting more power to the general assembly of bishops over the pope (an early example of the democratic process vs supreme monarch). The case of the Teutonic Knights vs Poland-Lithuanian also marked a shift in the church's aggressive war approach, by ruling against forced conversion and limiting crusader activity.

Council of Siena (1423)

• Location: Siena, Italy
• Key Figures:
• Pope Martin V
• Topics: Reform of Catholic Church after Council of Constance. Conciliarism. Condemnation of Hussites and Wycliffites. Reunification with Eastern Greek Church
• Outcome: New decrees against heresy. Failed to achieve unified reform. The council was dissolved and rescheduled a year later at the Council of Basel.
  

17. Council of Basel, Ferarra, and Florence (1431-1445)

• 
  Location: Basel (Switzerland), Ferrara (Italy), Florence (Italy)
  
• Convoked: Pope Martin V, Pope Eugene IV
• Attendance Count: 150
• President: Cardinal Giuliano Cesarini
• Key Participants:
• Pope Eugene IV
• Emperor Sigismund
• Nicholas of Cusa
• Byzantine Emperor John VIII Palaiologos
• Topics Discussed:
• Conciliarism (Authority of Council vs Pope)
• Church Reform
• Hussite Issues
• Reunion with Eastern Orthodox Church
• Declared Doctrine:
• Reaffirmed Haec Sancta (Council is superior to the pope)
• Formal union with Greek Orthodox Church
• Established Canon Laws:Clerical discipline
• Church Governance
• Compactata of Prague- compromise with moderate Hussites
• Decree of Union- formal reunion with East and West churches (later rejected)
• Sect Judgements: 
• Compromise with moderate faction of Hussites (known as Ultraquists)
• Deposed Pope Eugene IV
• Aftermath:
• Council established Antipope Felix V which began another schism of two popes for ten years
• Decree of Union between East and West was quickly rejected by majority of Eastern Church leaders
• Increasing reform movements as church shows signs of corruption, indulgences, clerical abuses, abuse of authority
• Summary: This council continued the debate of church reform pertaining primarily to conciliarism. While the Council of Constance had set the mandate, the pope quickly rejected that he should be inferior to a council. It was later revisited unsuccessfully in the Council of Siena in 1423 and resumed 8 years later with this council. This one was heavily divided by conflicting factions, and was even broken up into three phases at different locations. It reached extreme measures when the council decided to appoint their own antipope in Basel. Pope Eugene IV decided to resume the council in Ferarra and Florence and gained support by establishing compromise with the Eastern Church and the Hussites. The Eastern Church was once again in desperate need of Western aid and military support in the face of Ottoman invasions. The union was quickly rejected however even more so when the Byzantine Empire collapsed at the conquest of Constantinople in 1453. This schism of two popes only lasted ten years and was eventually reunited by 1449 where the council lost it's case and papal authority resumed. This marked the final collapse of conciliarism, and further advanced the reform movements against church corruption and abuse of power.

18. Fifth Council of Lateran (1512-1517)

• 
  Location: Rome, Italy (Basilica of St. John Lateran)
  
• Convoked: Pope Julius II, Pope Leo X
• Attendance Count: 90-120
• President: Pope Julius II, Pope Leo X
• Key Participants:
• Pope Julius (1512-1513)
• Pope Leo X (1513-1517)
• Cardinals of the Roman Curia
• Topics Discussed:
• Reform of the church-clerical discipline, corruption, education
• Assertion of papal authority over conciliarism
• Regulation of preaching and teaching
• Relationship between church and Renaissance humanism
• Printing and censorship of books
• Threat of the Ottoman Empire
• Financial and administrative reform
• Declared Doctrine:
• Reaffirmed papal supremacy over general council (rejected conciliarism)
• Confirmed the immortality of the soul
• Established Canon Laws:
• Approval process of all published books
• Improved standards for preaching
• Requirements for better education and discipline
• Regulation of Monti di Pieta (charitable lending institutions)
• Sect Judgements: 
• Condemned conciliarist movement
• Opposed humanist ideals that claimed the soul was not immortal
• Summary: This council was convoked to address the rising concern of humanism and Renaissance ideals but also bring an absolute end to the debate of conciliarism. In the wake of the printing press invention, the church passed a new decree to regulate and censor all published books (so as to control misguided ideas). It also addressed the concern of the Ottoman Empire which had just recently conquered Constantinople in 1453. It continued to reform the church to weed out corruption and tighten discipline among the clergy. Some often consider this council as coming close but still missing the mark on their serious reform of the corruption. This was the last major Catholic council before the Protestant Reformation (Martin Luther wrote his 95 Thesis the same year the council ended). Worth noting this was the first council held in Rome in nearly 300 years and made the Lateran Palace the place to host the most ecumenical councils.

19. Council of Trent (1545-1563)

• Location: Trent, Italy
• 
  Convoked: Pope Paul III, Pope Julius III, Pope Pius IV
  
• Attendance Count: 250 bishops
• President: Paul III, Julius III, Pius IV
  
• Key Participants:
• Pope Paul III (1545-1549)
• Pope Julius III (1550-1555)
• Pope Pius IV (1559-1563)
• St. Charles Borromeo
• Topics Discussed: 
• Response to Protestant Reformation
• Authority of Scripture and Tradition
• Nature of justification (faith vs works)
• The seven sacraments
• Reform of clergy discipline
• Roles of bishops
• The format of Mass and the Eucharist
• Church misconduct of indulgences, simony, absenteeism
• Declared Doctrine:
• Scripture and Tradition were the equal source of authority
• Justification of faith and works (not faith alone)
• Affirmation of Transubstantiation in Eucharist
• Importance of Confession, Penance, Priesthood
• Established Canon Laws: 130
• Required bishops to reside in dioceses
• Ended absentee leadership
• Mandated better discipline and moral standards
• Established seminaries to train priests
• Standardized the Mass (Tridentine Mass)
• Regulated indulgences, corruption, simony, and financial abuses
• Sect Judgements:
• Condemned Lutheranism, Calvinism, and other Protestant movements
• Rejected Protestant doctrine of Sola Scriptura (Scripture alone)
• Rejected Protestant doctrine of Sola Fide (Faith alone)
• Aftermath: 
• Catholic Counter Reformation Movement
• Expansion of censorship and doctrinal enforcement
• Global Missionary expansion (in Latin America, Asia, and Africa)
• New religious orders (Jesuits)
• Summary: Considered one of the most important Catholic ecumenical councils that saved the church in the face of the Protestant Reformation. This council served as the initial launching pad of the Catholic Counter-Reformation and Catholic Revival movements. It carefully reviewed Protestant doctrine and rejected with a clear and thorough theological response. Some key examples were declaring that one cannot be saved thru faith alone, but also thru grace and charitable works. It also clarified that both the scripture and the church tradition were the sources of authority in opposition to Protestants claims that only saw the bible as the true source. The council of Trent completely cleaned out the misbehavior within the clergy with strict rules against corruption, simony, indulgences, etc. It emphasized the importance of the Eucharist and the sacraments. It also standardized the order of mass which stood in practice for the next 400 years until it was updated during the Second Vatican Council. This dispute between the Catholic Church and the Protestant Reformation was heavily contested throughout the 1500-1600s, thru religious wars such as the French Wars of Religion (1562-1598), Dutch Revolt (1568-1648), and Thirty Years War (1618-1648). Eventually by 1648 at the Peace of Westphalia both sides had begun to recognize one another, and it was seen as another schism similar to the Eastern Orthodox.

Councils of Milan (1560-1580)

• Location: Milan, Italy
• Key Figures:
• St. Charles Borromeo (Archbishop of Milan)
• Topics: Counter-Reformation. Tridentine Mass. Establishment of seminaries and priest training. Improvement of catechism, preaching, and education. Enforcement of church structure.
• Outcome: Resumed the initiatives established at the Council of Trent. Strengthened discipline, education, and organization of the church as well as the laypeople. The Tridentine Mass was practiced in Latin for nearly 400 years until it was reformed at Vatican Council II in 1962.

Synod of Jerusalem (1672)

• Location: Jerusalem, Ottoman Empire
• Key Figures:
• Patriarch Dosietheus II of Jerusalem
• Eastern Orthodox Bishops
• Topics: Rejection of Calvinist Protestant doctrines promoted by Cyril Lucaris. Orthodox alignment with Catholicism against Protestantism.
• Outcome: Confession of Dosietheus doctrine rejected Protestant theology and firmly clarified Orthodox beliefs. One of the most authoritative post-Byzantine councils, that improved East-West relations during Counter Reformation.

Synod of Pistoia (1786)

• Location: Pistoia, Duch of Tuscany (modern day Italy)
• Key Figures:
• Scipione de Ricci (Bishop of Pistoia)
• Grande Duke Peter Leopold of Tuscany (later became Holy Roman Emperor Leopold III)
• Topics: Church reform tied to Enlightenment ideas. Jansenism (salvation thru God's grace). Gallicanism (Limiting papal authority). Criticism of devotions. Reform of liturgy and monastic orders. Greater state control over the church.
• Outcome: Approved locally but rejected by Catholic church under Pope Pius VI in 1794. Bishop Ricci was forced to recant his positions. This was a famous example of an anti-papal movement that was popular during the Enlightenment Age.

Synod of Constantinople (1872)

• Location: Constantinople, Ottoman Empire
• Key Figures:
• Patriarch Anthimus VI of Constantinople
• Patriarchs of Alexandria, Antioch, and Jerusalem
• Topics: Bulgarian Question (conflict between Greek and the fast-growng Bulgarian chuch). Condemnation of phyletism (national church organizations). Nationalism vs Traditional Roman Church Structure.
• Outcome: Phyletism condemned as heresy. Confirmed church must not be divided by national ethnic borders. Created schism with Bulgarian Orthodox Church (which was not officially recognized by the Catholic Church until 1945).

Councils of Baltimore (1852, 1866, 1884)

• Location: Baltimore, USA
• Key Figures: 
• Francis Patrick Kenrick (Archbishop of Baltimore, 1852)
• Martin John Spalding (Archbishop of Baltimore, 1866)
• James Gibbons (Archbishop of Baltimore, 1884
• Topics: Organization of Catholic Church in United States. Uniform discipline, education, structure, seminaries. Relations with American Protestantism and Nativism (native born Americans showing hostility towards immigrants)
• Outcome: Strengthened the unity of the Catholic Church in America. Reinforced loyalty to Roman pope. Established the Catholic University of America. Standardized parochial schools for most parishes.

20. First Council of the Vatican (1869-1870)

• 
  Location: Vatican City (St. Peter's Basilica)
  
• Convoked: Pope Pius IX
• Attendance Count: 750 bishops and abbots
• President: Pope Pius IX
• Key Participants:
• Pope Pius IX
• Cardinals and bishops from across the world
• Cardinal Henry Edward Manning (England)
• Bishop Felix Dunpanloup (France)
• Archbishop John Ireland (US)
• Topics Discussed: 
• Nature of faith and reason
• Challenges of modernism, rationalism, and secular philosophy
• Role and authority of the papacy
• Relationship between church and secular politics
• Defense of traditional Catholic doctrine vs modern ideological movements
• Biblical inspiration
• Declared Doctrine:
• Dei Filius- Affirmed that faith and reason are compatible
• Papal Infallibility- Pope is incapable of error as the successor of St. Peter
• Sect Judgements: 
• Condemned atheism, rationalism, and materialism
• Aftermath:
• Papal Infallibility causes another schism- Old Catholic Schism
• Rome is conquered by the Kingdom of Italy
• Pope is declared prisoner of Vatican for 59 years, until the Roman Question is settled with the establishment of Vatican City
• Summary: This council was called a few years after the establishment of the Kingdom of Italy which was now encroaching on Papal State territory. It was the first council held in over 300 years, making it the largest ecumenical gap in church history. It reviewed all the modern concepts brought on by the Enlightenment, Scientific Revolution, and the Industrial Revolution. It defined a new Dogmatic Constitution known as Dei Filius which condemned the philosophy of rationalism, anarchism, communism, socialism, liberalism, materialism, modernism, pantheism, naturalism, secularism, and atheism. It's most important declaration was it's new dogma of papal infallibility, which elevated the pope's primacy and supremacy as unmatched and undisputable. This essentially claimed that the pope was the vicar of Christ, the top authority of the church, who was to be revered by all bishops since he was the successor of Saint Peter. The council came to an abrupt halt since Rome was invaded and captured by the Kingdom of Italy. This was still productive in defining the relationship between faith and science as compatible, however it caused another schism of those who disagreed with the concept of papal infallibility.

First Plenary Council of Latin America (1899)

• Location: Rome, Italy
• Key Figures: 
• Pope Leo XIII
• Cardinal Domenico Maria Jacobini (Holy See of the Vatican)
• Archbishop Mariano Casanova of Santiago (Chile)
• 50 bishops across Latin America
• Topics: Unifying church across Latin America. Secularism. Relations with freemasonry and Protestantism. Church reform with seminaries and catholic education. Relations with modern governments.
• Outcome: Issued 1,000 decrees on discipline, education, and church life in Latin America. Strengthened unity in Latin America while still falling under Roman papal authority.

21. Second Council of the Vatican (1962-1965)

• Location: Vatican City (St. Peter's Basilica)
• Convoked: Pope John XXIII
• 
  Attendance Count: 2600 bishops (largest in Church history)
  
• President: Pope John XXIII, Pope Paul VI
• Key Participants:
• Pope John XXIII
• Pope Paul VI
• Karl Rahner
• Joseph Ratzinger (later Pope Benedict XVI)
• Yves Congar
• Topics Discussed:
• Role of the church in the modern world
• Relationship between faith and contemporary society
• Liturgy
• The role of bishops and the laity
• Religious freedom
• Relations with other Christians and other religions
• Church teaching on scripture and revelation
• Declared Doctrine:
• Sacrosanctum Concilium- Reform of the liturgy in vernacular languages, not just Latin
• Lumen Gentium- Nature and structure of the church
• Dei Verbum- Divine revelation and scripture
• Gaudium et Spes- Chuch's relationship with the modern world
• Sect Judgements: Promoted ecumenism (unity with other Christians)
• Improved relations with non-Christian religions
• Summary: This is the most recent ecumenical council that ultimately sought to bring the church up to date, referred to as aggiornamento. This was in response to the modern technological world and it's rise of individual freedom that may have been contributing to a decline of religious life. This council established a newer outlook on the church as one that was friendlier and more welcoming verse it's long history of condemnation. It modernized many elements of the church liturgy, primarily that it could be spoken in Native language, not strictly Latin. It also opened the doors to more participation from the laity to encourage the practice of the faith (such as responding to the priest, reading scripture, serving as Eucharistic ministers, partaking in the offertory procession, as well as congregational singing and prayer). It also put out an olive branch to other Christian denominations, accepting them and promoting unity. It even improved relations with non-Christians groups such as Judaism, Islam, Hinduism, and Buddhism. It ultimately permitted religious freedom and tolerance, ending centuries of forced coercion The purpose here was to reshape the church's defensive strict approach with one that was portrayed as a positive welcoming light.