Migration of Serbs To The Balkans
According to the work named "De administrando imperio", written by the Byzantine emperor Constantine VII Porphyrogennetos (912-959), Balkanic Serbs originating from pagan White Serbs who lived on the other side of present-day Turkey (name used for Hungary), in the area that they called Bojki. Neighbors of White Serbs were Frankish State and pagan Great or White Croatia. Porphyrogennetos claims that after two brothers inherited administration over Serbia (i.e. White Serbia) from their father, one of them, with half of the people, escaped to the Byzantine Empire (i.e. to the Balkans), which was governed by emperor Heraclius (610-641). According to German historian L. A. Gebhardi, two brothers that inherited administration over White Serbia were sons of prince Dervan.
In the Balkans, Serbs settled first around rivers Tara, Ibar, Drina and Lim (in the present-day border region of Serbia, Montenegro and Bosnia and Herzegovina, but also Dalmatia), and joined with surrounding South Slavic tribes that came to the Balkans earlier (in the 6th century) and the Paleo-Balkan people. Over time, the South Slavic and mostly Illyrian tribes of this territory mixed with the Serbs and also adopted Serb name as their own.
Another part of the White Serbs did not migrated southwards, but remained in the Elbe region. Descendants of these White Serbs are the present day Lusatian Serbs (Sorbs), who still live in the Lusatia (Lužica, Lausitz) region of eastern Germany.
There are also opinions that data from "De administrando imperio" that describes Serb migration to the Balkans is not correct and that Serbs came to the Balkans from Eastern Slavic lands, together with other South Slavs.
The Emperor Constantine III (641) transferred a part of the Slavs from the Balkans (Vardar region) to Asia Minor. There these migrants founded the city of Gordoservon, the name of which gives grounds for supposing that among its founders there were Serbs. The city was also known under names Gordoserbon and Servochoria.
Read more about this topic: Origin Of The Serbs