Council of Constantinople in AD 381 (First Council of Constantinople)
Location: Church of Hagia Irene, Istanbul
Year: AD 381
Organized by: the Roman Emperor Theodosius I
Attendees: 150 bishops (no representation of Western Church)
Summary: Repudiated Arianism and Macedonianism, declared that Christ is "born of the Father before all time", revised the Nicene Creed in regard to the Holy Spirit
Notes: At the Council of Constantinople, the earlier council's decision on the deity of Jesus was confirmed and Arianism was formally declared a heresy. They also voted that Holy Spirit was the third Person of the Trinity. Almost all of the churches abandoned Arianism after this council.
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