Greatly fragmented and weakened by the Fourth Crusade of 1204 and its aftermath, the Byzantine Empire shrank considerably during the ensuing century. The Palaiologos dynasty, which reasserted Greek Orthodox control of Constantinople in 1261, concentrated on rebuilding the city and, to assuage the Latins, swore allegiance to Rome, but paid little attention to its rural regions, especially those in Asia Minor, where the Ottoman (Osmanli) Turks were advancing. A rogue company of Catalan knights marauding in Anatolia did not help, and nor did the Black Death plague, which broke out in 1347. With the death in 1341 of Emperor Andronikos III, an internal power struggle began in the Byzantine ruling class between his young heir John V Palaiologos and the leader of a regency, John Kantakouzenos, resulting in a debilitating civil war that was to last until 1357. This instability enabled the Serbian King Stefan Dušan from 1347 to conquer Albania and the northern Greek regions of Macedonia, reaching as far south as the Gulf of Corinth. In October 1352 at Demotika, John’s V largely Serbian forces were defeated by Kantakouzenos’ largely Ottoman ones, and two years later, thanks to an earthquake, the Ottomans were able to capture the strategic fortress at Gallipoli, on the European mainland. By 1355 the Byzantines were maintaining an Empire in name only, and the Ottoman invasion of Europe was about to begin.
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