The catepanate was named after the fortified town of Ras, eponymous for the historical region of Raška (Latin: Rascia).

[1][2] In the middle of the 6th century, during the reign of Byzantine emperor Justinian I (d. 565), a fortress of Arsa (Greek: Ἄρσα) in the province of Dardania was refortified, as attested by historian Procopius.

Up to the middle of the 10th century, the fortress of Ras was a borderline stronghold between the Principality of Serbia and First Bulgarian Empire, as attested by the Byzantine emperor and historian Constantine VII Porphyrogenitus (d. 959) in his work De Administrando Imperio.

It was established as a Byzantine stronghold in Serbian lands, but its territorial jurisdiction can not be precisely determined, but Serbia probably also was conquered.

[1] After 976, the region was dominated by the restored Bulgarian Empire, that had complex relations with neighbouring Serbian princes.