Manuel II stood on friendly terms with the victor in the Ottoman civil war, Mehmed I (1402–1421), but his attempts to meddle in the next contested succession led to a new assault on Constantinople by Murad II (1421–1451) in 1422. During the last years of his life, Manuel II relinquished most official duties to his son and heir John VIII Palaiologos, and went back to Europe searching for assistance against the Ottomans, this time to the King Sigismund of Hungary, staying for two months in his court of Buda. Sigismund (after suffering a defeat against the Turks in the Battle of Nicopolis in 1396) never rejected the possibility of fighting against the Ottoman Empire. However, with the Hussite wars in Bohemia, it was impossible to count on the Czech or German armies, and the Hungarian ones were needed to protect the Kingdom and control the religious conflicts. Unhappily Manuel returned home with empty hands from the Hungarian Kingdom, and in 1424 he and his son were forced to sign an unfavourable peace treaty with the Ottoman Turks, whereby the Byzantine Empire had to pay tribute to the sultan. Manuel II died on 21 July 1425.