Amidst the turbulence of the Ottoman conquest of the Balkans in the early 15th century, the region's Christian rulers lost several battles, such as the Battle of Kosovo and the siege of Veliko Tarnovo. Despot Stefan Lazarević had to maintain the Serbian Despotate in a delicate balance between the Ottomans and Hungarians. Around 1403, he accepted the Hungarian vassalage from King Sigismund and established the new capital in Belgrade, which was ceded to him as an award. After Stefan's death in 1426, Đurađ Branković, Stefan's nephew and successor, had to return Belgrade to the Hungarians. To compensate for this loss, Đurađ decided to build a new capital, and the choice fell to Smederevo.