was on campaign in Transylvania, rode to his soldiers' camp to inform them of the good news. The following day John fell ill, and he died on 21 or 22 July. Before his death he persuaded those present at his death bed to take an oath that they would prevent the transfer of his realm to Ferdinand. Childhood Accession Soon after John Zápolya died, his treasurer, George Martinuzzi, hurried to Buda to secure John Sigismund's inheritance. On Martinuzzi's proposal, the Diet of Hungary elected John Sigismund king on 13September 1540, but he was not crowned with the Holy Crown of Hungary. The Diet proclaimed Queen Isabella and George Martinuzzi, along with two powerful lords, Péter Petrovics and Bálint Török, the guardians of the infant monarch. In August, Ferdinand's envoys had demanded the transfer of the late John Zápolya's realm to Ferdinand in accordance with the Treaty of Várad. Peter Perényi, who had been the commander of Zápolya's troops in Upper Hungary, and Franjo Frankopan, Archbishop of Kalocsa, soon deserted to Ferdinand. The wealthy Stephen Majláth expelled most of John Sigismund's supporters from Transylvania in an attempt to seize the province for himself. Ferdinand's envoy, Hieronymus Łaski, informed Suleiman of the Treaty of Várad, asking the sultan to consent to the unification of Hungary under Ferdinand's rule. Instead, the sultan stated that he supported John Sigismund and had Łaski arrested. Ferdinand's army seized Visegrád, Vác, Pest, Tata and Székesfehérvár in October, but could not capture Buda. His military commander, Wilhelm von Roggendorf, again laid siege to Buda on 4May 1541. Suleiman left Istanbul at the head of a large army in June to take advantage of the new civil war in Hungary. On his command, Petru Rareș, Prince of Moldavia, captured Stephen Majláth and forced the Transylvanian Diet to swear fealty to John Sigismund in late July. Roggendorf lifted the siege of Buda before Suleiman reached the town on 26August. Suleiman said that he had come to protect John Sigismund's interests, but also announced that he wanted to see the infant king, because he had heard rumours about Isabella's having actually given birth to a daughter. Six Hungarian lords (including George Martinuzzi and Bálint Török) accompanied John Sigismund to the sultan's camp on 29August. During the meeting, janissaries entered Buda, saying that they wanted to see the town. This turned out to be a trick that enabled them to seize the