lazar succeeded his father as despot on 24 december 1456, but his reign was cut short by his death on 28 january 1458. despoina helena and lazar's brother stefan seized power and began negotiating a marriage between her eldest daughter and stephen tomašević, the elder surviving son of king thomas of bosnia. the intent was to consolidate an alliance against the threat of the expanding ottoman empire, which had already reduced the despotate of serbia to a strip of land governed from the smederevo fortress. stephen tomašević arrived to smederevo during the holy week of 1459, taking over the fortress and the government on 21 march. the marriage was celebrated on 1 april, the first sunday following easter. the bride soon afterwards joined the catholic church and adopted the name maria.