In 325, the first Ecumenical Church Council, convened by emperor Constantine, was held in Nicea’s emperor’s palace. In 381, the second Ecumenical Church Council, convened by emperor Theodosius I, was held in Constantinople’s Church of Holy Peace (Hagia Sophia). In 431, the third Ecumenical Church Council, convened by emperor Theodosius II, was held in Ephesus’ Church of Mary. In 449, an unofficial church council, later called the “Gangster Council,” convened by emperor Theodosius II, was held in Ephesus’ Church of Mary. In 451, the fourth Ecumenical Church Council, convened by emperor Marion, was held in Chalcedon’s Church of Saint Euphemia. In 553, the fifth Ecumenical Church Council, convened by emperor Justinian, was held in Constantinople’s Church of Holy Wisdom (Hagia Sophia). In 680-681, the sixth Ecumenical Church Council, convened by emperor Constantine IV, was held in Constantinople’s Church of Holy Wisdom (Hagia Sophia). In 787, the seventh Ecumenical Church Council, convened by emperor Constantine VI and his mother, Irene, was held in Nicea’s Church of Holy Wisdom (Hagia Sophia).
...
Today, Eastern Orthodox, Roman Catholic, and Protestant churches generally accept the doctrinal conclusions of these councils, which defined the true (orthodox) Christian faith.
Source: Dr. Andrew Jackson - "The Ecumenical Church Councils of the Early Church (325-787)"
https://www.drandrewjackson.com/the-ecumenical-church-of-councils-of-the-early-church-325-787/