De Administrando Imperio
Slavs settled in the Balkans during the 6th and 7th centuries. According to "De Administrando Imperio", there existed three Slavic polities on the territory of modern Montenegro: Duklja, roughly corresponding to the southern half; Travunia, the west; and Principality of Serbia, the north. Duklja emerged as an independent state during the 11th century, initially held by the Vojislavljević dynasty, later to be incorporated into the state of the Nemanjić dynasty. De Administrando Imperio also mentions that the area, along with the majority of the Roman province of Dalmatia, has been mostly settled by Serbs.