Compact Bulgarian population persisted throughout the Provadiya Plateau, Devnya Valley, and Eastern Stara Planina.
After the liberation of 1878, with the exodus of most Turks and Greeks and the migrations of Bulgarians from other parts of Bulgaria, mostly Stara Planina, as well as North Dobruja, Asia Minor, Bessarabia, and later from Macedonia and Eastern Thrace, ethnic diversity gradually gave way to Bulgarian predominance.