Christianity in Turkey
Constantinople became established in the ecclesiastical hierarchy at the Council of Constantinople in 381. Second only to Rome, the legendary origins of the Patriarchate of Constantinople go back to St. Andrew, Metrophanes and Alexander of Constantinople. Constantinople's primacy over the Patriarchates of Alexandria and Antioch was reaffirmed at the Council of Chalcedon in 481, after which the papacy in Rome supported Constantinople in its dispute with Alexandria over monophysitism. Later, when Rome sought to assert its primacy over Byzantium, the Eastern Orthodox church developed the doctrine of pentarchy as a response.
Byzantine architecture
The Byzantine era is usually dated from 330 CE, when Constantine the Great moved the Roman capital to Byzantium, which became Constantinople, until the fall of the Byzantine Empire in 1453. However, there was initially no hard line between the Byzantine and Roman empires, and early Byzantine architecture is stylistically and structurally indistinguishable from Roman architecture. This terminology was introduced by modern historians to designate the medieval Roman Empire as it evolved as a distinct artistic and cultural entity centered on the new capital of Constantinople (modern-day Istanbul) rather than the city of Rome and its environs.