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.
Rise of the Ottoman Empire
In April 1453, Mehmed laid siege to Constantinople. Although the city's defenders, led by Giovanni Giustiniani under Emperor Constantine XI Palaiologos's (1448–53) authority, put up a heroic defense, without the benefit of outside aid their efforts were doomed. The formerly impregnable land walls were breached after two months of constant pounding by Mehmed's heavy artillery. In the predawn hours of 29 May 1453, Mehmed ordered an all-out assault on the battered ramparts. After a brief but vicious melee at the walls in which Giustiniani was severely injured coupled with Ottoman troops breaching the walls through a sally port door left open, the Ottoman troops were able to breach the walls and rout the defenders. According to Christian sources, Emperor Constantine died bravely rushing into the oncoming Ottoman troops not to be seen again. However, according to Ottoman sources such as Tursun Beg he threw off his mantle and attempted to flee before being cut down by an injured Ottoman soldier. The Ottoman Army broke through and swept over the city. Constantinople, for a millennium considered by many Europeans the divinely ordained capital of the Christian Roman Empire, fell to Mehmed and was transformed into what many Muslims considered the divinely ordained capital of the Islamic Ottoman Empire. The fabled city's imperial legacy lived on. After the conquest, the sultan had his grand vizier Çandarlı Halil Pasha killed. His following four granviziers were of devshirme origin. During the growth of the Empire Turks seldom were appointed to the high positions.Following the capture of Constantinople, Mehmed built the Topkapı Palace in 1462 and moved the Ottoman capital there from Adrianople. Mehmed had himself titled "Kaiser-i-Rum", or "Roman Caesar", and modelled the state after the old Byzantine Empire, thinking of himself as the successor to the Roman throne. Later, when he invaded Otranto, his goal was to capture Rome and reunite the Roman Empire for the first time since 751. Justinian's cathedral of Hagia Sophia was converted into an imperial mosque, as eventually were numerous other churches and monasteries. The rights of non-Muslim inhabitants were protected to ensure continuity and stability for commercial activities. Never fully recovered from the sack of 1204, and suffering from Byzantium's two centuries of near poverty, Constantinople by the time of Mehmed's conquest was but a hollow shell of its former self. Its population had dwindled, and much property was either abandoned or in a state of disrepair. The sultan immediately began to repopulate the city. Civic and private properties were offered to the public to entice much-needed skilled artisans, craftsmen, and traders of all religions and ethnicities back to the city. Newly conquered Constantinople rapidly grew into a multiethnic, multicultured, and bustling economic, political, and cultural center for the Ottoman state, whose distant frontiers guaranteed it peace, security, and prosperity.