Slavic speakers in Ottoman Macedonia
Slavic-speakers inhabiting the Ottoman-ruled region of Macedonia had settled in the area since the Slavic migrations during the Middle Ages and formed a distinct ethnolinguistic group. While Greek was spoken in the urban centers and in a coastal zone in the south of the region, Slav-speakers were abundant in its rural hinterland and were predominantly occupied in agriculture.
Source: Wikipedia — Slavic speakers in Ottoman Macedonia (CC BY-SA 4.0)