Nicopolis at its core and Arta as its capital. Epirus, and the city of Ioannina in particular, became a haven for Greek refugees from the Latin Empire of Constantinople for the next half-century. The Despotate of Epirus ruled over Epirus and western Greece as far south as Naupaktos and the Gulf of Corinth, much of Albania (including Dyrrhachium), Thessaly, and the western portion of Macedonia, extending its rule briefly over central Macedonia and most of Thrace following the aggressive expansionism of Theodore Komnenos Doukas, who established the Empire of Thessalonica in 1224. During this time, the definition of Epirus came to encompass the entire coastal region from the Ambracian Gulf to Dyrrhachium, and the hinterland to the west up to the highest peaks of the Pindus mountain range. Some of the most important cities in Epirus, such as Gjirokastër (Argyrokastron), were founded during this period. The oldest reference to Albanians in Epirus is from a Venetian document dating to 1210, which states that "the continent facing the island of Corfu is inhabited by Albanians". Kosta Giakoumis believes that the use of hypothetical immigrations to explain the accounts of Albanian presence in Epirote territory prior to the 13th-14th century is somewhat arbitrary. In 1337, Epirus was once again brought under the rule of the restored Byzantine Empire. In 1348, taking advantage of the civil war between the Byzantine emperors John V Palaiologos and John VI Kantakouzenos, the Serbian king Stefan Uroš IV Dušan conquered Epirus, with a number of Albanian mercenaries assisting him. The Byzantine authorities in Constantinople soon re-established a measure of control by making the Despotate of Epirus a vassal state, but meanwhile Albanian clans invaded and seized most of the region. The Albanian Losha and Zenevisi clans founded two short-lived principalities, centered in Arta (1358–1416) and Gjirokastër (1386–1411) respectively. Only the city of Ioannina remained under Greek control during this time. Although Albanian clans gained control of most of the region by 1366/7, their continued division into rival clans meant that they could not establish a single central authority. Ioannina became a center of Greek resistance to the Albanian clans. The Greeks of Ioannina offered power to three foreign rulers during this time, beginning with Thomas II Preljubović (1367–1384), followed by Esau de' Buondelmonti (1385–1411), and finally Carlo I Tocco (1411–1429). The latter finally succeeded in ending the rule of the Albanian clans and unifying Epirus under his