 It met from May to July 381 in the Church of Hagia Irene and was affirmed as ecumenical in 451 at the Council of Chalcedon.When Theodosius ascended to the imperial throne in 380, he began on a campaign to bring the Eastern Church back to Nicene Christianity.Theodosius wanted to further unify the entire empire behind the orthodox position and decided to convene a church council to resolve matters of faith and discipline.