Christianity in Credo: Late Antiquity

The doctrine of Arius, pronounced heretical at the Council of Nicaea, which asserted that Christ was not of one substance with the Father, but a creature raised by the Father to the dignity of Son of God.

Schismatic movement among Christians of N Africa (fl. 4th cent.), led by Donatus, bishop of Casae Nigrae (fl. 313), and the theologian Donatus the Great or Donatus Magnus (d. 355). The schism arose when certain Christians protested the election of the bishop of Carthage, charging that his consecration by Felix, bishop of Aptunga, was invalid because Felix was considered a traitor.

Opposition to the religious use of images. Veneration of pictures and statues symbolizing sacred figures, Christian doctrine, and biblical events was an early feature of Christian worship.

The doctrine that Christ was two distinct persons, divine and human, implying a denial that the Virgin Mary was the mother of God. It is attributed to Nestorius and survives in the Iraqi Church.

A heretical doctrine, first formulated by Pelagius, that rejected the concept of original sin and maintained that the individual takes the initial steps towards salvation by his own efforts and not by the help of divine grace.

From Cultural Studies: Holidays Around the World
The Greek word theotokos means “god-bearer,” or “mother of God.” Mary was declared to be Theotokos as a result of the Council of Ephesus, held in 431.

From The Columbia Encyclopedia
1st ecumenical council, convened by Roman Emperor Constantine the Great to solve the problems raised by Arianism.

From The Columbia Encyclopedia
Second ecumenical council. It was convened by Theodosius I, then emperor of the East and a recent convert, to confirm the victory over Arianism.

From The Columbia Encyclopedia
3d ecumenical council, convened by Theodosius II, emperor of the East, and Valentinian III, emperor of the West, to deal with the controversy over Nestorianism.

From Britannica Concise Encyclopedia
(451) Fourth ecumenical council of the Christian Church, held in Chalcedon (modern Kadiköy, Turkey). Called by the emperor Marcian, it approved the creeds of Nicaea (325) and Constantinople (381; later known as the Nicene Creed). It also approved the Tome of Pope Leo I confirming the two distinct natures in Christ and rejecting the Monophysite heresy. The council then explained these doctrines in its own confession of faith.

From The Columbia Encyclopedia
Regarded generally as the fifth ecumenical council. It was convened by Byzantine Emperor Justinian I to settle the dispute known as the Three Chapters.

From The Columbia Encyclopedia
Regarded by Roman Catholic and Orthodox Eastern churches as the sixth ecumenical council. It was convoked by Byzantine Emperor Constantine IV to deal with Monotheletism. The council was attended by more than 150 bishops from all over the world, and it was presided over by the papal legates.

From The Columbia Encyclopedia
7th ecumenical council, convened by Byzantine Empress Irene. Called to refute iconoclasm, the council declared that images ought to be venerated (but not worshiped) and ordered them restored in churches.