Albanian-speakers of Western Thrace migrated towards today's European Turkey (Eastern Thrace), especially near Istanbul. Many Muslim Albanians achieved high office in Ottoman society and many of them, most notably the Köprülü family, became Grand Viziers of the Empire. The majority of the Albanian emigration came from Northern Kosovo and the Korça region of Albania. Descendants of this immigrants would later play an important role in the National Renaissance of Albania. The number of Albanians that resided in the region is unknown, as statistical data of the Ottoman Empire were based on religious identification (millets). Thus, the Orthodox Albanians were part of the Rûm millet,
History of the Eastern Orthodox Church in the Ottoman Empire, culminating in the Armenian, Greek and Assyrian genocides. As a result, the 20th century saw a sharp decline of the number of Orthodox Christians, and of Christians in general, in the Anatolian peninsula amidst complaints of Turkish governmental repression of various Eastern and Oriental Orthodox groups. During the Lausanne Conference in 1923, the Turkish and Greek sides after some discussions accepted the proposal of a population exchange. Muslims in Greece (save the ones in Eastern Thrace) were expelled to Turkey, and Greek Orthodox people in Turkey (save the ones in Istanbul) were expelled to Greece. In