In 1439 the Ottoman army, headed by the sultan Murad II himself, again attacked and sacked Serbia. Despot Đurađ fled to Hungary in May 1439, leaving his son Grgur Branković and Jerina's brother Thomas Kantakouzenos to defend Smederevo. After three months of siege, Smederevo fell on August 18, 1439, while Novo Brdo resisted conquest for two entire years, falling on June 27, 1441. At that point the only free part of the Despotate that remained was Zeta. The latter, however, was soon attacked by the Venetians and by Voivode Stefan Vukčić Kosača. The last of Đurađ's cities in the region were conquered in March 1442.
