COUNCIL OF JERUSALEM —AD 49/50 Decisions made on conversions and circumcision. It was decided that it was not necessary for converts to submit to the Old Covenant laws like circumcision.
1. NICAEA I —AD 325 Nicene Creed; divinity of Christ, condemned Arianism; Easter observance set.
2. CONSTANTINOPLE I —AD 381 Expanded the Creed; defeated Arianism; condemned Macedonians who the denied divinity of the Holy Spirit.
3. EPHESUS —AD 431 Defended Mary as the mother of God; condemned Nestorianism which held there were two distinct persons in the Incarnate Christ.
4. CHALCEDON —AD 451 Condemned Monophysitism by defining two distinct natures of Christ: Jesus fully human and divine.
5. CONSTANTINOPLE II —AD 553 Confirmed Chalcedon; condemned heresies like Monotheletism that held Christ had only one will.
6. CONSTANTINOPLE III —AD 680-81 Defeat of Monotheletism by defining two wills of Christ as two distinct principles of operation in unity of purpose.
7. NICAEA II —AD 787 Regulated veneration of holy images; condemned Iconoclasts and defined that sacred images may be honored without idolatry.
8. CONSTANTINOPLE IV —AD 869-870 Condemned teachings of Photius Bishop of Constantinople. Last council attended by Eastern Church; beginning of the Great Eastern Schism.
9. LATERAN I —AD 1123 First council after the Great Eastern Schism. Condemned practice of lay princes in investiture of bishops. Called for recovery of the Holy Land.
10. LATERAN II —AD 1139 Enacted reforms suggested by St. Bernard of Clairvaux; condemned certain heresies; declared null and void decrees by the deceased antipope Anticletus II.
11. LATERAN III —AD 1179 Established the Sacred Conclave as voting body to elect Pope by 2/3rds majority; condemned the Albigensian and Waldensian heresies.
12. LATERAN IV —AD 1215 Defined ex cathedra: from the chair of Peter and "There is but one Universal church, outside of which there is no salvation." Set in stone the term Transubstantiation for the mystery of the Eucharist. Ordered annual confession and Easter Communion.
13. LYONS I —AD 1245 Called for a new Crusade. Excommunicated and deposed Emperor Frederick II.
14. LYONS II —AD 1274 Filioque clause officially added to the Creed. Attempted reconciliation with Eastern Catholics. Decreed that papal elections should begin 10 days after death of the Pope.
15. VIENNE —AD 1311-1312 Reformation of the clergy and Catholic universities; called for a new Crusade; dealt with the charges against the Knights Templar; defined the relation of the soul to the human body; condemned false mysticism.
16. CONSTANCE —AD 1414-1418 Put an end to the Western Schism (Avignon Popes vs. Rome); issued reform decrees in "head and members", condemned Wycliffe and Hus.
17. BASEL-FLORENCE —AD 1431(38)-1445 Affirmed papal primacy against Conciliarists who said a general council was superior to the Pope; attempted reunion with Eastern church.
18. LATERAN V —AD 1512-1517 Disciplinary decrees-defined the relation of Pope to a general council, condemned philosophers who taught human soul was mortal and only one for all mankind; discussed religious upheaval in Germany caused by Luther.
19. TRENT —AD 1545-1563 Condemned Lutheranism and other errors in teaching that resulted from Protestant movement; proclaimed Bible and Tradition as rule of faith; defined doctrine on the Mass, the sacraments, justification, purgatory, indulgences, invocation of saints, veneration of sacred images, issued decrees on marriage and clerical reform.
20. VATICAN I —AD 1869-1870 Defined the nature of revelation and faith, the relation of faith and reason; and infallibility of the Pope when speaking ex cathedra in matters of faith and morals. Condemned pantheism, materialism, deism, naturalism, and fideism.
21. VATICAN II —AD 1962-1965 Convoked by Pope John XXIII "mainly to more effectively preserve and present the sacred deposit of Christian doctrine." Sixteen documents reaffirmed the principles of Catholic faith and morality, authorized numerous changes in the Eucharistic liturgy, the ritual of the sacraments, and in the church's administrative structure. These documents and liturgical reforms defined the Church in the modern age.