The Serbs, like the Croats, are believed by most scholars to be a purely Slavic people who originated in the Ukraine, though some now argue that both the original Serbs and Croats were Central Asian Sarmatian nomads who entered Europe with the Huns in the fourth century CE.

The theory proposes that the Sarmatian Serbs settled in a land designated as White Serbia, in what is now Saxony and Western Poland.

The Sarmatian Serbs, it is argued, intermarried with the indigenous Slavs of the region, adopted their language, and transferred their name to the Slavs.

The tribal designation Serboi first appears in the first century Geography of Ptolemy (book 5, 9.21) to designate a tribe dwelling in Sarmatia, probably on the Lower Volga River.