Jan Zapolya was born in Slovakia in 1487. He came from a noble Hungarian family. In 1505 he led the Diet (Assembly) of Rakos, which passed a decision preventing princes who were not of Hungarian descent from being elected king.
Thereupon, he became one of the royal candidates of the nobles. Jan Zapolya, who was appointed Transylvanian Voivode in 1511, bloodily suppressed the peasant uprising against the nobles in 1514.
The Hungarian campaign of the Ottoman sultan Suleiman the Magnificent ended with the victory of Mohács in 1526. Zapolya was elected king by a section of Hungarian nobles in November 1526. However, the opposing Hungarian nobles elected Austrian Archduke Ferdinand as king, causing a civil war that lasted two years.
Zapolya, who was defeated by Ferdinand, appealed to the Ottomans. Zapolya's position was strengthened when Suleiman the Magnificent re-entered Hungary in 1529.
John Zápolya or Szapolyai (1487 – 22 July 1540), was King of Hungary (as John I) from 1526 to 1540. His rule was disputed by Archduke Ferdinand I, who also claimed the title King of Hungary. He was Voivode of Transylvania before his coronation, from 1510 to 1526.
Hungarian lands were divided between Zapolya and Ferdinand in 1533. Jan Zapolya, who did not comply with the agreement he made in 1538, left his son Sigismund in his place and died in Transylvania in 1540.