The First Council of Constantinople (second ecumenical council) was called by Theodosius I in 381 to confirm the Nicene Creed and deal with other matters of the Arian controversy . Saberians were controversed too. In confirming the Nicene Creed, it also amended it by adding the final section regarding the Holy Spirit.

Pope Timothy I of Alexandria, Meletius of Antioch, Gregory Nazianzus, and Nectarius successively presided. Gregory Nazianzus was made patriarch, but soon resigned from the position of See a few months later, and Nectarius was then put in his place.

Seven canons, four of these doctrinal canons and three disciplinary canons, are attributed to the Council and accepted by both the Eastern Orthodox Church and the Oriental Orthodox Churches; the Roman Catholic Church accepts only the first four.