The Eastern Hungarian Kingdom is a modern term coined by some historians to designate the realm of John Zápolya and his son John Sigismund Zápolya, who contested the claims of the House of Habsburg to rule the Kingdom of Hungary from 1526 to 1570. The Zápolyas ruled over an eastern part of Hungary, and the Habsburg kings ruled the west. The Habsburgs tried several times to unite all Hungary under their rule, but the Ottoman Empire prevented that by supporting the Eastern Hungarian Kingdom.

Maximilian II was Holy Roman Emperor from 1564 until his death in 1576. A member of the Austrian House of Habsburg, he was crowned King of Bohemia in Prague on 14 May 1562 and elected King of Germany on 24 November 1562. On 8 September 1563 he was crowned King of Hungary and Croatia in the Hungarian capital Pressburg. On 25 July 1564 he succeeded his father Ferdinand I as Holy Roman Emperor.