Treaty of Nagyvárad in the context of "John Zápolya"

The Eastern Hungarian Kingdom (Hungarian: keleti Magyar Királyság [ˈkɛlɛti ˈmɒɟɒr ˈkiraːjʃaːg]) 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 (Ferdinand and Maximilian) 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.

The exact extent of the Zápolya realm was never settled because both the Habsburgs and the Zápolyas claimed the whole kingdom. A temporary territorial division was made in the Treaty of Nagyvárad in 1538. The Eastern Hungarian Kingdom is considered the predecessor of the Principality of Transylvania (1570–1711), which was established by the Treaty of Speyer.