First Council of Constantinople (381 AD)
First Council of Constantinople (381 AD) (Second Ecumenical Council, affirmed the full deity of the Holy Spirit and completed the Creed): The First Council of Constantinople, convoked by Emperor Theodosius I with 150 orthodox bishops, expanded the Nicene Creed into the definitive Niceno-Constantinopolitan Creed, explicitly confessing the full divinity of the Holy Spirit as 'the Lord, the Giver of Life, who proceeds from the Father, who with the Father and the Son is worshiped and glorified'. It is closely linked with Second Council of Constantinople (553 AD) (Fifth Ecumenical Council, condemned the Three Chapters to clarify neo-Chalcedonian orthodoxy): The Second Council of Constantinople was convoked by Emperor Justinian I with 165 bishops to reconcile Miaphysite Christians by reaffirming Cyrillian neo-Chalcedonian orthodoxy and condemning the 'Three Chapters'—the persons and writings of Theodore of Mopsuestia, Theodoret of Cyrus, and Ibas of Edessa accused of Nestorian sympathies.
