 During the first years of the war, forces of the new regency prevailed. In the wake of several anti-aristocratic uprisings, most notably that of the Zealots in Thessalonica, a majority of the cities in Thrace and Macedonia came under regency control. With assistance from Stefan Dušan of Serbia and Umur Beg of Aydin, Kantakouzenos successfully reversed these gains. By 1345, despite Dušan's defection to the opposition and the withdrawal of Umur, Kantakouzenos retained the upper hand through the assistance of Orhan, ruler of the Ottoman emirate. The June 1345 murder of megas doux Apokaukos, the regency's chief administrator, dealt the regency a severe blow. Formally crowned as emperor in Adrianople in 1346, Kantakouzenos entered Constantinople on 3 February 1347. By agreement, he was to rule for ten years as the senior emperor and regent for John V, until the boy came of age and ruled alongside him. Despite this apparent victory, subsequent resumption of the civil war forced John VI Kantakouzenos to abdicate and retire to become a monk in 1354.
