The First Council of Constantinople occurred in AD 381 in the city of the same name (modern Istanbul, Turkey). It is considered the second of the Ecumenical Councils, after Nicea in 325. At the Council of Constantinople, Christian bishops convened to settle several doctrinal disputes prompted by unrest in the religious leadership of the city. While not as memorable as the Council of Nicea, the council dealt a fatal blow to Arianism, clarified the language used to describe the Trinity, and sharpened the distinctions between the Eastern and Western branches of the church.
The immediate motivation behind calling the first Council of Constantinople was a series of controversies. The Council of Nicea had met more than fifty years prior to settle the Arian controversy, a debate over whether or not Jesus was fully divine. Despite the council’s nearly 300-to-2 decision rejecting Arianism, the view persisted and continued to cause division among Christians. Constantinople itself was considered an “Arian” city until a new Emperor, Theodosius I, attempted to forcibly replace its church leaders with non-Arians.
This attempted purge did not go over well, and further unrest ensued. Theodosius attempted to install Gregory Nazianzus as Bishop of Constantinople. However, before Gregory could be formally consecrated, a rival group broke into the cathedral and attempted to consecrate Maximus the Cynic, instead. Their consecration ritual was interrupted by an angry mob, leading Theodosius to ask Pope Damasus for advice. Damasus’s order was for Theodosius to call a meeting of bishops who would formally reject Maximus and settle (again) the Arian controversy.
True to form, the beginning of the Council of Constantinople was marred by controversy. The man first selected to preside over the Council, Meletius of Antioch, died soon after the council opened. Gregory was then elected to lead the discussions, but a late-arriving contingent of bishops opposed both Gregory’s leadership of the council and his installment as Bishop of Constantinople. This led to an argument that threatened to derail the entire process. Gregory offered to resign both offices, a solution that ended the controversy and allowed the council to continue.
Once under way, the Council of Constantinople again strongly denounced Arianism. Council members also discussed the hierarchy of bishops, rules for bringing heretics back into the church, and disciplinary issues among church leaders. Central to these discussions were careful applications of correct terminology when discussing the Trinity. In particular, it extended the language of the Nicene Creed to more precisely reflect the orthodox position. Here is the Nicene Creed with the changes made by the Council of Constantinople in brackets:
We believe in one God, the Father Almighty, Maker [of heaven and earth], and of all things visible and invisible, and in one Lord Jesus Christ, the [only-begotten] Son of God, begotten of the Father [before all worlds], Light of Light, very God of very God, begotten, not made, being of one substance with the Father; who for us men, and for our salvation, came down [from heaven], and was incarnate [by the Holy Ghost of the Virgin Mary], and was made man; he [was crucified for us under Pontius Pilate, and] suffered, [and was buried], and the third day he rose again, [according to the Scriptures, and] ascended into heaven, [and sitteth on the right hand of the Father]; from thence he shall come [again, with glory], to judge the quick and the dead; [whose kingdom shall have no end]. And in the Holy Ghost, [the Lord and Giver of life, who proceedeth from the Father, who with the Father and the Son together is worshiped and glorified, who spake by the prophets. In one holy catholic and apostolic Church; we acknowledge one baptism for the remission of sins; we look for the resurrection of the dead, and the life of the world to come. Amen.]
Much as a prior emperor, Constantine, had called the Council of Nicea to determine the boundaries of “orthodox” Christianity, Theodosius I intended the Council of Constantinople to unify Roman Christians under a common core of belief. To some extent, this goal was achieved, in that several doctrinal points were clarified. Arianism began to decline and eventually withered away.
At the same time, the Council of Constantinople heightened the growing divide between the Eastern and Western Churches. One of the council’s declarations proclaimed that “the Bishop of Constantinople, however, shall have the prerogative of honor after the Bishop of Rome, because Constantinople is New Rome.” This generated disagreement over the relative importance of the five major Christian jurisdictions: Rome, Antioch, Alexandria, Constantinople, and Jerusalem. When the Great Schism occurred centuries later, one of the primary disagreements was the hierarchy of Rome and Constantinople.