During the reign of Stefan Dushan, 1331–55, taking advantage of the Byzantine civil war of 1341–1347, the area of Elbasan, Krujë, Berat and Vlora (Principality of Valona) were added to the nascent Serbian Empire. In 1346 the patriarchal throne was permanently established at the Pec Monastery. In 1346, after Epirus and Thessaly were added to the Serbian Empire, Dusan was crowned the emperor of the Serbs and Greeks in the city of Skopje. A legal code was promulgated and the bishopric of Pec was proclaimed a patriarchate which established the Serbian Orthodox Church as independent from Constantinople. Prizren became the political capital of the Serbian Empire and was the chief Serbian city of trade and commerce. After the death of Dushan in 1355, Kosovo was ruled by King Vukasin Mrnjavcevic, who was a co-ruler with Tsar Uros, the last of the Nemanjic rulers.