Second Ecumenical Council

The Second Ecumenical Council or First Council of Constantinople took place in 381. It differentiated the faith from Arianism, and this differentiation was accepted by churches in the West. However, it declared Constantinople as the second center of the Christian faith after Rome, which was not completely accepted by the bishops of Rome, Antioch, and Alexandria.

Christian Churches that accept the Second Ecumenical Council on issues of faith, not necessarily on the issue of Constantinople:

• Roman Catholicism

• Eastern Orthodoxy

• Oriental Orthodoxy

• Assyrian Church of the East

• Anglicanism

• Lutheranism

Reference

First Council of Constantinople

https://www.newworldencyclopedia.org/entry/First_Council_of_Constantinople#The_proceedings