Jan Zápolský / John Zápolya
After this defeat, John turned for help to Istanbul, where he found a great ally – Sultan Suleiman, who sensed territorial gains in Europe. Already in the autumn of 1528 John was able to return to Transylvania, and later Ottoman allies drove Ferdinand out of Hungary. Suleiman stopped only in 1529 at the siege of Vienna, from where he had to retreat back home. However, Ferdinand’s army advanced back into Hungary behind the sultan’s army, which again successfully conquered many territories. Only Buda was not captured a second time. John had to invite Sultan Suleiman to Hungary again. Ferdinand’s and Suleiman’s armies struggled until Ferdinand and John realised that Suleiman was by far the biggest beneficiary of the conflict. Also under pressure from King Sigismund I the Old of Poland, whose eldest daughter John had been courting for some time, they concluded a peace treaty (the Peace of Velkovaradin) in 1538.
Source https://cs.wikipedia.org/wiki/Jan_Zápolský