Original sentence: Singidunum experienced occupation by successive invaders of the region—Huns, Sarmatians, Ostrogoths and Avars—before the arrival of the Slavs (Serbs) around AD 630
Edited sentence: Singidunum experienced occupation by successive invaders of the region—Huns, Sarmatians, Ostrogoths and Avars—before the arrival of the Slavs (Bulgarians) around AD 630