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 part of Turkey after the Treaty of Lausanne. Western Thrace was ceded to the Entente in December 1919, after which many Bulgarians left the region, while many Greeks moved in. The Government of the Entente (led by French general Sharpe) held its own census in 1920, according to which Western Thrace had a population of 204,700, of whom: Turks 36.5% (74,720 Muslims), Bulgarians 32.2% (65,927 = 54,079 Christians and 11,848 Muslims), Greeks 27.4% (56,114 Christians), Jews 1.5% (2985) Armenians 0.9% (1880), others 3066. At the time this census was conducted, a part of the Greek population of Ksanthi, who left