page_title: State church of the Roman Empire
section_title: Legacy
hierarchical_section_title: State church of the Roman Empire / Legacy
caption_attribution_description: English: Photograph of the emblem found above the front entrance of the Ecumenical Patriarchate of Constantinople. Perhaps a symbol of the Ecumenical Patriarchate of Constantinople itself.
context_page_description: With the Edict of Thessalonica in 380 AD, Emperor Theodosius I made Nicene Christianity the Empire's state religion. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church each claim to stand in continuity with the church to which Theodosius granted recognition, but do not look on it as a creation of the Roman Empire.
  Earlier in the 4th century, following the Diocletianic Persecution of 303–313 and the Donatist controversy that arose in consequence, Constantine had convened councils of bishops to define the orthodoxy of the Christian faith, expanding on earlier Christian councils. A series of ecumenical councils convened by successive emperors met during the 4th and 5th centuries, but Christianity continued to suffer rifts and schisms surrounding the issues of Arianism, Nestorianism, and Miaphysitism. In the 5th century, the Western Empire decayed as a polity: invaders sacked Rome in 410 and in 455, and Odoacer, an Arian barbarian warlord, forced Romulus Augustus, the last nominal Western Emperor, to abdicate in 476.
context_section_description: Following the schism between the Eastern and Western Churches, various emperors sought at times but without success to reunite the Church, invoking the notion of Christian unity between East and West in an attempt to obtain assistance from the Pope and Western Europe against the Muslims who were gradually conquering the empire's territory. But the period of the Western Crusades against the Muslims had passed before even the first of the two reunion councils was held.
  Even when persecuted by the emperor, the Eastern Church, George Pachymeres said, "counted the days until they should be rid not of their emperor (for they could no more live without an emperor than a body without a heart), but of their current misfortunes". The church had come to merge psychologically in the minds of the Eastern bishops with the empire to such an extent that they had difficulty in thinking of Christianity without an emperor.
  In Western Europe, on the other hand, the idea of a universal church linked to the Emperor of Constantinople was replaced by that in which the Roman see was supreme. "Membership in a universal church replaced citizenship in a universal empire. Across Europe, from Italy to Ireland, a new society centered on Christianity was forming."
  The Western Church came to emphasize the term Catholic in its identity, an assertion of universality, while the Eastern Church came to emphasize the term Orthodox in its identity, an assertion of holding to the true teachings of Jesus. Both churches claim to be the unique continuation of the previously united Chalcedonian Church, whose core doctrinal formulations have been retained also by many of the churches that emerged from the Protestant Reformation, including Lutheranism and Anglicanism.
caption: Emblem of the Patriarch of Constantinople, based on the imperial symbol adopted in the 11th century