Louis II of Hungary
In 1526, King Louis II of Hungary was killed at the Battle of Mohács. The Hungarian Diet elected Zápolya as their new king. Archduke (and future Holy Roman Emperor) Ferdinand also claimed the crown, and was elected by a rump Diet. This conflict resulted in war between the rivals. In 1527, Ferdinand invaded Hungary and captured Buda while Zápolya was distracted by a peasant uprising. Zápolya quickly turned to meet Ferdinand, but could only bring limited forces to the field.