In the year before the Council of Constantinople in 381, the Trinitarian version of Christianity became the official religion of the Roman Empire when Emperor Theodosius I issued the Edict of Thessalonica in 380, which recognized the catholic orthodoxy of Nicene Christians as the Roman Empire's state religion. Historians refer to the Nicene church associated with emperors in a variety of ways: as the catholic church, the orthodox church, the imperial church, the imperial Roman church, or the Byzantine church, although some of those terms are also used for wider communions extending outside the Roman Empire. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church all claim to stand in continuity from the Nicene church to which Theodosius granted recognition.
Icon depicting Constantine and the bishops of the Council of Nicaea (325). The centrally placed and haloed Emperor holds the Creed of the First Council of Constantinople (381).
Missorium of Emperor Theodosius I, who declared Nicene Christianity to be the State religion of the Roman Empire. This piece was found in Almendralejo.
The Hagia Sophia basilica in Constantinople, for centuries the largest church building in the world.
Oriental Orthodox Churches
Videos
The Oriental Orthodox Churches are Eastern Christian churches adhering to Miaphysite Christology, with approximately 50 million members worldwide. The Oriental Orthodox Churches adhere to the Nicene Christian tradition. Oriental Orthodoxy is one of the oldest branches in Christianity.
Image: Էջմիածնի Մայր Տաճար
Image: S. George Syr Orth Cathedral Damascus
Image: Cairo Abbasiya Mark Entrance
Image: Aramana