Technically, the council of Jerusalem was not an ecumenical council, though it was the very first church council. Ecumenical Councils are solemn assemblies of bishops and the pope. They are convened by the pope to discuss Church doctrine, discipline, and pastoral matters. The pope is the essential unifying factor at the council. The gift of infallibility in matters of faith and morals is a characteristic of an ecumenical council. Each council produces a further clarification of Christ’s teachings. There have been twenty-one ecumenical councils.
Nicea in 325 AD. Condemned Arianism and formulated the Nicene Creed.
First Constantinople in 381 AD. Condemned the Macedonians and confirmed the Nicene Creed.
Ephesus in 431 AD. Condemned Nestorianism and declared Mary as the Mother of God.
Chalcedon in 451 AD. Condemned Monophysitism and declared that Christ had two distinct natures—divine and human—in one divine Person.
Second Constantinople in 553 AD. Condemned certain persons who followed
Nestorianism: Theodore of Mopsuestia, Theodoret of Cyrrhus, and Ibas of Edessa.
Third Constantinople in 680–681 AD. Condemned Monothelites and declared that Christ had two wills—human and divine.
Second Nicea in 787 AD. Condemned the Iconoclasts and defended the veneration of sacred images without it being idolatry.
Fourth Constantinople in 869–70 AD. Condemned Photius as the false Patriarch of Constantinople and reaffirmed Ignatius as the authentic one.
First Lateran in 1123 AD. Issued decrees on simony, celibacy, lay investiture and confirmed the Concordat of Worms.
Second Lateran in 1139 AD. Ended the papal schism and enacted reforms.
Third Lateran in 1179 AD. Condemned Albigenses and Waldenses heresies and decreed papal elections by two-thirds majority.
Fourth Lateran in 1215 AD. Issued a decree on annual Communion and for the first time used the term “transubstantiation.”
First Lyons in 1245 AD. Condemned Frederick II and planned a second crusade. Second Council of Lyons in 1274 AD. Temporarily reunited with the Greek churches and regulated the time papal elections can begin—ten days after the death of the pope.
Vienne in 1311–12 AD. Suppressed the Knights Templar and enacted reforms. Constance in 1414–18 AD. Condemned Wyclif and Hus and put an end to the Western Schism.
Florence in 1431–45 AD. Affirmed papal primacy and attempted to further effect unity with the Greek Church.
Fifth Lateran in 1512–17 AD. Condemned Neo-Aristotelians, who taught that the soul was mortal and there was only one for all of humanity (that is, humans all shared one soul).
Trent in 1545–63 AD. Condemned Protestantism and enacted major reforms. First Vatican in 1869–70 AD. Defined papal infallibility and condemned pantheism, materialism, deism, naturalism, and fideism.
Second Vatican in 1962–65 AD. Promulgated sixteen documents, which reaffirmed principles of the Catholic faith and morals. Called for reforms in the Church liturgy and sacramental life.