In 1416 he participated in a tournament in Perpignan in which he defeated the well-known knight John II of Aragon and Navarre. The following year, he became the "starost" of Kruszwica. In 1419 he went to Sigismund again, as a deputy of King Władysław II, to ask for the hand of Sophia of Bavaria, the widow of Sigismund's brother Wenceslaus of Bohemia. Subsequently, Zawisza participated in the Hussite Wars on the side of King Sigismund. During Sigismund's defeat at Kutná Hora (21 December 1421), Zawisza was taken prisoner by the Hussites and subsequently released in return for a high ransom.