since at that time he was childless. Queen of Hungary In April 1538, just two months after the Treaty of Nagyvárad, Bishop Stjepan Brodarić arrived to Kraków to negotiate timing and conditions for the wedding of Isabella and John Zápolya. Polish nobles considered the wedding to be ill-conceived and not beneficial, but it proceeded. On 15 January 1539, five hundred Hungarian knights arrived to Kraków. The betrothal took place on 26 January. The per procura wedding date is not known exactly, but it was probably between 28 January and 2 February. After the ceremony, Isabella departed towards Hungary. Her dowry was 32,000 ducats in cash plus property worth another 6,000 ducats. Through Buda she reached Székesfehérvár where she met John Zápolya for the first time on 22 February. He granted her the towns of Solymos, Lippa, Déva, Csicsó, Tokaj, parts of Debrecen and Regéc castles. The next day the wedding ceremony took place and Isabella was crowned as Queen of Hungary. The wedding feast continued for a week in Buda. The married life was short and not happy. 20-year-old Isabella had to deal with 52-year-old husband who complained of gout and overall ill health. In spring 1540, Zápolya traveled to quell a revolt in Transylvania by . Isabella stayed in Buda as she was pregnant. Their son John Sigismund Zápolya was born on 7 July 1540. Zápolya succeeded in subduing the rebels, but he died on 22 July from cerebral hemorrhage. Regency According to the Treaty of Nagyvárad, John Zápolya was to be succeeded by Archduke Ferdinand of Austria, but Hungarian nobles, particularly Bishop George Martinuzzi, refused to abide by it and in September 1540 elected the infant John Sigismund as King of Hungary and Isabella as his regent. Ferdinand invaded Hungary and besieged Buda where Isabella and her son sought shelter. The city withstood the first siege in November 1540 and the second siege in May 1541 was lifted by Suleiman the Magnificent, Sultan of the Ottoman Empire. She did not receive help from her father Sigismund I the Old. Suleiman preferred a fragmented Hungary but understood that only he could protect it from the Habsburgs. Therefore, he converted most of Hungary to pashaliks (province governed by a pasha) and only Transylvania and lands east of the Tisza River (known as Temesköz) were given to John Sigismund and Isabella as his guardian. These appointments were accepted by the Transylvanian