The Apostolic Council in Jerusalem, ~49-50
The false opinion that Christians must keep the Law of Moses in order to be saved was condemned.
=> Ebionites, a separate community. They believed in Christ but held that the Law of Moses must be kept.
The I Ecumenical Council — I Nicaea, 325, 318 bishops
Condemnation of Arius. Condemnation of the heresy of Arius, who taught that Christ is not God but a special being created by God.
The Creed. The first 7 articles of the Creed were established.
The date of Pascha. Pascha is to be celebrated on the first Sunday after the full moon that falls after the spring equinox.
The II Ecumenical Council — I Constantinople, 381, 150 bishops
Condemnation of Macedonius. The heresy of Macedonius, who taught that the Holy Spirit is not God but a power of the Father and the Son, was condemned.
The Creed completed. 5 more articles were added to the Creed.
The III Ecumenical Council — Ephesus, 431, 160 bishops
Condemnation of Nestorius. Condemnation of the heresy of Nestorius, who taught that Christ is an ordinary man in whom, after his birth, God dwelt as in a temple.
Definitions. Christ is true God and true man. The Virgin Mary is the Theotokos (Mother of God).
A ban on changing the Creed.
=> Separation of the Chaldeans (the Assyrian Church of the East)
The IV Ecumenical Council — Chalcedon, 451, 520 bishops
Condemnation of Monophysitism. The heresy of Eutyches was condemned, who taught that the human nature of Christ was completely absorbed by the divine, so that only the divine nature remained in Him, without the human.
Definitions. In the person of the Son of God two natures (divine and human) are united: without confusion, without change, without division, without separation. The natures did not merge into one, neither of the natures was changed as a result of the union, and the union is without division and forever.
=> Separation of the Copts (the Coptic Orthodox Church of Alexandria) / the Syrians (the Jacobite Church) / the Armenians (the Armenian Apostolic Church)
The V Ecumenical Council — II Constantinople, 553, 165 bishops
Condemnation of Origen. Origen was condemned, together with his false teaching on the finiteness of the torments of hell and the final salvation of absolutely everyone[1].
Condemnation of the writings:
of Theodore of Mopsuestia (he himself was also condemned as the teacher of Nestorius);
of Ibas of Edessa (suspicion of Nestorianism);
of Theodoret of Cyrus (his criticism of the teaching of St. Cyril of Alexandria).
The VI Ecumenical Council — III Constantinople, 680, 170 bishops
Condemnation of Monothelitism. Condemnation of the heresy that taught one will in Christ (only the divine).
Definitions. In Christ there is, as in God, a divine will, and, as in man, a human will. The human will is obedient to the divine will.
The VII Ecumenical Council — II Nicaea, 787, 219 bishops and 131 monks
Condemnation of Iconoclasm. Condemnation of the heresy that taught that church icons should be regarded as idols and allowed neither depicting Christ and the saints nor venerating these images.