From the above it is clear that the Patriarch Euthymius, reflecting a general perception, recognizes Macedonia as part of Greek land.
Source: E. Kaluzniacki, Werke Des Patriachen von Bulgarien Euthymius (1375-1393),. Nach den besten Handschriften, Wien 1901.
So even in Medieval Bulgarian sources it was well known in Macedonia were living Greeks. However Turks didnt keep their promises for long.
During the reign of Anastasius, Bulgarians started to conquer this land, they passed to Bidynio and firstly begun to conquer the Lower land of Ochrid and later all of it.
Source: Die Slavische Manasses-Chronik. Ach der Ausgabe von oan Bogdan. Muncen, Wilhelm Fink Verlag 1966, page 115.
Therefore we learn that even Serbs knew Macedonia and Thrace consisted of Greek cities.