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,
Northern Thrace Northern Thrace Northern Thrace or North Thrace (, ) (as opposed to Western Thrace and East Thrace to the south) constitutes the northern and the largest part of the historical region of Thrace. Bulgarian Thrace is located in Southern Bulgaria and refers to the whole territory south of the Balkan Mountains and east of the Mesta River; to the Greek and Turkish borders in south and to the Black Sea in east. It encompasses Sredna Gora, the Upper Thracian Plain and 90% of the Rhodopes. The climate differs from continental to transitional continental and mountainous. The highest temperature recorded in