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,
Albanian-speakers of Western Thrace while Muslims were categorised alongside Turks. Among this population, Orthodox Albanians in Eastern Thrace resided in partly homogeneous communities, either villages or neighborhoods, and were mainly descendants of immigrants from the Korça region. At the conclusion of the Greco-Turkish War of 1919–1922, Greece and Turkey signed the Treaty of Lausanne, which included a population exchange between the two countries. The treaty used religion as the indicator of national affiliation, thus including populations without ethnic provisions, even Albanians, in the population exchange. Under this treaty the Muslims of Greece were exchanged with the Christians of Turkey, with an exception of the