Vlad was released before the end of the year but was forced to leave his two young sons as hostages in the Ottoman court. He was restored in Wallachia with Ottoman support in 1443. He remained neutral during Hunyadi's "Long Campaign" against the Ottoman Empire between October 1443 and January 1444, but he sent 4,000 horsemen to fight against the Ottomans during the Crusade of Varna. With the support of a Burgundian fleet, he captured the important Ottoman fortress at Giurgiu in 1445. He made peace with the Ottoman Empire in 1446 or 1447, which contributed to the deterioration of his relationship with Hunyadi. Hunyadi invaded Wallachia, forcing Vlad to flee from Târgoviște in late November, where he was killed at a nearby village.