Christian Councils

oodegr.com The Ecumenical Synods

britannica.com First Council of Nicaea - 325 - first ecumenical council

Council of Nicaea, also called First Council of Nicaea, (325), the first ecumenical council of the Christian church, meeting in ancient Nicaea (now İznik, Turkey). It was called by the emperor Constantine I, an unbaptized catechumen, who presided over the opening session and took part in the discussions. He hoped a general council of the church would solve the problem created in the Eastern church by Arianism, a heresy first proposed by Arius of Alexandria that affirmed that Christ is not divine but a created being.

britannica.com Council of Constantinople - 381 - second ecumenical council

Council of Constantinople, (381), the second ecumenical council of the Christian church, summoned by the emperor Theodosius I and meeting in Constantinople. Doctrinally, it adopted what became known to the church as the Niceno-Constantinopolitan Creed (commonly referred to as the Nicene Creed), which effectively affirmed and developed the creed earlier promulgated at the Council of Nicaea in 325 (Creed of Nicaea). The Nicene Creed, however, was probably not an intentional enlargement of the Creed of Nicaea but rather an independent document based on a baptismal creed already in existence. The Council of Constantinople also declared finally the Trinitarian doctrine of the equality of the Holy Spirit with the Father and the Son. Among the council’s canons was one giving the bishop of Constantinople precedence of honour over all other bishops except the bishop of Rome, “because Constantinople is the New Rome.”

Though only eastern bishops had been summoned (about 150 in all), the Greeks claimed this council to be ecumenical. Pope Damasus I in Rome appears to have accepted the creed but not the canons, at least not the canon upon the precedence of Constantinople. (Rome indeed accepted the precedence of Constantinople, next to Rome, only during the life of the Latin Empire of Constantinople, created in the 13th century during the Fourth Crusade.) In both East and West, nevertheless, the council came to be regarded as ecumenical.

britannica.com Council of Chalcedon - 451 - fourth ecumenical council

Council of Chalcedon, the fourth ecumenical council of the Christian Church, held in Chalcedon (modern Kadiköy, Tur.) in 451. Convoked by the emperor Marcian, it was attended by about 520 bishops or their representatives and was the largest and best-documented of the early councils. It approved the creed of Nicaea (325), the creed of Constantinople (381; subsequently known as the Nicene Creed), two letters of Cyril against Nestorius, which insisted on the unity of divine and human persons in Christ, and the Tome of Pope Leo I confirming two distinct natures in Christ and rejecting the Monophysite doctrine that Christ had only one nature. The council then explained these doctrines in its own confession of faith.