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,
Western Thrace following years, the Central Powers (Germany, Austria-Hungary, and the Ottoman Empire), with which Bulgaria had sided, lost World War I and as a result Western Thrace was withdrawn from Bulgaria under the terms of the 1919 Treaty of Neuilly. Western Thrace was under temporary management of the Entente led by French General Charles Antoine Charpy. In the second half of April 1920 in San Remo conference of the prime ministers of the main allies of the Entente powers (except the US) Western Thrace was given to Greece. Throughout the Balkan Wars and World War I, Bulgaria, Greece and Turkey each