 Complete the following phrase:  The Ottoman Sultan Suleiman the Magnificent  nearly annihilated the Hungarian army in the Battle of Mohács on 29 August 1526. The twenty-year-old King Louis II  drowned in a stream fleeing from the battlefield. John Zápolya and Louiss brother-in-law, Ferdid of Habsburg, laid claim to the throne. For both claimants were elected kings at two separate Diets, Hungary was plunged into civil war. Regarding Hungary as a vassal state, Suleiman acknowledged John as the lawful king, but neither claimants could take control of the whole country. The two kings agreed to divide the country in the 1538 Treaty of Várad Oradea, Romania, but the childless John acknowledged Ferdids right to reunite Hungary after his death. Days before John died in 1540, his wife, Isabella Jagiellon, gave birth to a son, John Sigismund. Johns principal advisor, the Paulician monk, George Martinuzzi, persuaded Johns partisans to elect the infant boy king. Ferdids troops stormed into John Sigismunds eastern Hungarian kingdom, providing Suleiman with a pretext to intervene. The Ottoman army invaded Hungary and 