In the 1340s, taking advantage of a Byzantine civil war, the Serbian King Stefan Uroš IV Dušan conquered Epirus and incorporated it in his Serbian Empire. During this time, two Albanian states were formed in the region. In the summer of 1358, Nikephoros II Orsini, the last despot of Epirus of the Orsini dynasty, was defeated in battle against Albanian chieftains. Following the approval of the Serbian Tsar, these chieftains established two new states in the region, the Despotate of Arta and Principality of Gjirokastër. Internal dissension and successive conflicts with their neighbours, including the rising power of the Ottoman Turks, led to the downfall of these Albanian principalities to the Tocco family. The Tocco in turn gradually gave way to the Ottomans, who took Ioannina in 1430, Arta in 1449, Angelokastron in 1460, and finally Vonitsa in 1479.