In 1419, the death of Wenceslaus IV left Sigismund titular King of Bohemia, but he had to wait for seventeen years before the Czech Estates would acknowledge him. Although the two dignities of King of the Romans and King of Bohemia added considerably to his importance, and indeed made him the nominal temporal head of Christendom, they conferred no increase of power and financially embarrassed him. Entrusting the government of Bohemia to Sofia of Bavaria, the widow of Wenceslaus, he hastened into Hungary.

The Bohemians, who distrusted him as the betrayer of Hus, were soon in arms; and the flame was fanned when Sigismund declared his intention of prosecuting the war against heretics. Three campaigns against the Hussites ended in disaster although the army of his most loyal ally Stibor of Stiboricz and later his son Stibor of Beckov could hold the Hussite side away from the borders of the Kingdom. The Turks were again attacking Hungary. The king, unable to obtain support from the German princes, was powerless in Bohemia. His attempts at the diet of Nuremberg in 1422 to raise a mercenary army were foiled by the resistance of the towns; and in 1424 the electors, among whom was Sigismund's former ally, Frederick I of Hohenzollern, sought to strengthen their own authority at the expense of the king. Although the scheme failed, the danger to Germany from the Hussites led to the Union of Bingen, which virtually deprived Sigismund of the leadership of the war and the headship of Germany.