Treaty of Nagyvárad

{{short description|1538 agreement between claimants to the Hungarian throne}}

{{sources exist|date=April 2024}}

The Treaty of Nagyvárad (or Treaty of Grosswardein) was a secret peace agreement between Emperor Ferdinand I and John Szapolyai, rival claimants to the Kingdom of Hungary, signed in Grosswardein / Várad (modern-day Oradea, Romania) on February 24, 1538.István Keul, Early modern religious communities in East-Central Europe: ethnic diversity, denominational plurality, and corporative politics in the principality of Transylvania (1526–1691)], Brill, 2009, [https://books.google.com/books?id=5J09mqMWiogC&pg=PA40 p. 40] In the treaty, they divided Hungary between them according to the actual possession.

Ferdinand recognized Zápolya as John I, King of Hungary and ruler of two-thirds of the Kingdom, while Zápolya conceded the rule of Ferdinand over western Hungary, and recognized him as heir to the Hungarian throne, since Zápolya was childless.{{sfn | Bohnstedt | 1968 | p=8}}

But in 1540, just before Zápolya's death, his wife bore him a son, John Sigismund Zápolya, and the agreement failed. John Sigismund was elected King of Hungary{{sfn | Bohnstedt | 1968 | p=8}} as John II by the Hungarian nobility. Isabella asked Ottoman Sultan Suleyman I to help in the fight with Ferdinand and his successors that ensued, only to see Suleiman to prevail, declare John II a king, and placing himself as a regent. A large portion of Hungary became essentially a Turkish province, complete with Ottoman governor and garrison in Buda.{{sfn | Bohnstedt | 1968 | p=8}}