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,
Bulgarian Catholic Apostolic Vicariate of Thrace Bulgarian Catholic Apostolic Vicariate of Thrace The Bulgarian Catholic Apostolic Vicariate of Tracia (informally Tracia of the Bulgarians) was the second missionary, pre-diocesan jurisdiction of the Bulgarian Greek Catholic Church "sui iuris" (Eastern Catholic, Byzantine Rite in Bulgarian language). As Apostolic Vicariate it was exempt, i.e. directly dependent on the Holy See, and entitled to a titular bishop. It was established on 7 April 1883 as Bulgarian Catholic Apostolic Vicariate of Tracia alias Hadrianopolis (after its see Adrianople, now Edirne, in Turkish Thrace) on Ottoman Turkish and Bulgarian territory in Thrace split off from the Bulgarian Catholic Apostolic Vicariate of