First Council of Constantinople

The ecumenical council held in Constantinople in 381, convened under Emperor Theodosius I. It reaffirmed Nicene Christianity and issued a canon granting Constantinople precedence after Rome.

First Council of Nicaea: The council held at Nicaea in 325 that rejected Arianism and produced an early form of the Nicene Creed. The 381 council reaffirmed Nicaea’s confession of the Son’s divinity.
Canon 3 of the First Council of Constantinople: A canon of the 381 council assigning the bishop of Constantinople precedence of honor after the bishop of Rome. This ruling directly established the city's ecclesiastical precedence.
Arian controversy: A long-running dispute over the relationship between the Father and the Son in Christian theology. The controversy remained politically powerful when the council convened.
Niceno-Constantinopolitan Creed: The expanded form of the Nicene Creed associated with the councils of Nicaea and Constantinople. It became the council’s most enduring doctrinal legacy.
Nicene Creed: A Christian confession of faith originating at Nicaea and expanded at Constantinople. The council’s doctrinal work is chiefly associated with its expanded creed.
Bishop of Constantinople: The chief bishop of Constantinople, whose office later developed into the Ecumenical Patriarchate. The council’s ranking canon elevated this office among major sees.
Meletian schism: A division in the church of Antioch between followers of Meletius and those aligned with Paulinus. The rival Antiochene claimants complicated the council’s effort to organize eastern church leadership.
Ecumenical Patriarchate of Constantinople: The office and institution headed by the archbishop of Constantinople in Eastern Orthodox Christianity. The precedence granted in 381 contributed to its later status.
Arianism: A Christian theological position that held the Son to be subordinate to the Father and not co-eternal with him. The council condemned teachings associated with Arianism while affirming the Son’s full divinity.
Edict of Thessalonica: A decree issued by Theodosius I and his co-emperors in 380 that endorsed Nicene Christianity as imperial orthodoxy. It set the imperial policy that the council reinforced the following year.

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