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 . In confirming the Nicene creed, it also amended it by adding the final section regarding the Holy Spirit.

Meletius of Antioch, Gregory Nazianzus, and Nectarius successively presided. Gregory Nazianzus was made patriarch, but soon resigned, and Nectarius was then put in his place.

Seven canons, four doctrinal and three disciplinary, are attributed to the council and accepted by the Greek Orthodox Church, but the Roman Catholic Church accepts only the first four.\n