Origin hypotheses of the Serbs
The Serbs trace their history to the 6th- and 7th-century Slavic migrations to the Balkans. Settling in various parts of the Balkans, Early Slavs assimilated local Byzantine populations (primarily descendants of different paleo-Balkan peoples) and other former Roman citizens.
Source: Wikipedia — Origin hypotheses of the Serbs (CC BY-SA 4.0)