The strategically important city of Valona, on the coast of modern Albania, had been fought over repeatedly between the Byzantines and various Italian powers in the 13th century. Finally conquered by Byzantium in ca. 1290, it was one of the chief imperial holdings in the Balkans. Byzantine rule lasted until the 1340s, when the Serbian ruler Stefan Dušan, taking advantage of a Byzantine civil war, took Albania. Valona fell in late 1345 or early 1346, and Dušan placed his brother-in-law, John Asen, brother of the Bulgarian Tsar Ivan Alexander, in charge of Valona as his capital, and with Kanina and Berat as his main fortresses. According to some scholars, however, Dušan had captured Valona and Kanina already in 1337. The extent of John's authority over this territory is unclear; it is not known whether he was limited to the rule of these fortified cities, or whether his authority was more extensive, with the various local chieftains of central Albania reporting to him as a representative of Dušan.