John Zápolya
John Sigismund's father, John Zápolya, was the wealthiest Hungarian lord in the early . After the Ottoman Sultan, Suleiman the Magnificent, inflicted a crushing defeat on the Hungarian army in the Battle of Mohács, the majority of the noblemen elected John Zápolya king in 1526. However, a group of influential lords proclaimed Ferdinand I, Archduke of Austria, king in the same year. Hungary fell into a civil war that lasted for decades.