sentences:  He did not hesitate to launch an attack against the weakened kingdom, whose smaller, badly led army (approximately 26,000 Hungarian soldiers compared to 45,000 Ottoman soldiers) was defeated on 29 August 1526 at the Battle of Mohács.Thus he became influential in the Kingdom of Hungary, while his semi-vassal, named John Zápolya and his enemy Ferdinand I both claimed the throne of the Kingdom.Suleiman went further and tried to crush Austrian forces, but his Siege of Vienna in 1529 failed after the onset of winter forced his retreat.