In the Battle of Mohács, the army of the Kingdom of Hungary under King Ludwig II and Pál Tomori suffered a crushing defeat on August 29, 1526 against the Ottoman army under Süleyman I at Mohács in southern Hungary. The Ottomans were soon able to conquer large parts of Hungary and Croatia.
In later centuries, the defeat of Mohács became as central to Hungarian history as the Battle of Blackbird Field (1389) was to Serbian history, or the Battle of White Mountain (1620) to Czech history. All three defeats became national myths, symbols in which collective identity was consolidated in the age of rising nationalism.
While Hungary had weakened the defense forces needed to fight the Ottomans in 1514 through the peasant uprising of György Dózsa and its suppression, the Ottomans had expanded their empire in 1521 by conquering Belgrade in a north-westerly direction. Another campaign against Hungary followed in 1526. Süleyman had demanded tribute from Hungary; when Hungary refused to pay, he marched north with an army of about 60,000 to 70,000 men (which included 10,000 horsemen ("sipahis") and 12,000 janissaries as elite troops). King Ludwig left Tolna with his army on August 15th. According to the Romanian historian Nicolae Iorga, the army, totaling around 25,000 to 40,000 men, consisted mostly of peasants. In contrast, the German historian Michael Klein points out that the Hungarian peasantry had behaved passively in the Turkish war. Forced into serfdom in the wake of the quashed uprising of 1514, the peasants saw no difference between the oppression of the Hungarian magnates and that of the Turks. Since the nobility, on the other hand, did not trust the peasants, the army going into battle had very few foot troops.
The army camp was set up near the village of Mohács; here they wanted to wait for more troops. The Transylvanian prince Johann Zápolya had received several requests to bring his troops to the king. But he was a long time coming. The Ottoman army crossed the Drava River on August 20th and faced the Hungarian army on the 29th.
The Hungarians wanted to route the Ottomans without prior knowledge of the Ottoman order of battle. When an Ottoman unit of Sipahis then showed up, the entire Hungarian heavy cavalry attacked, although only part of the Hungarian army (28,000 to 30,000 men) had been prepared for battle. But the Sipahis retreated in an orderly manner and lured the Hungarians into an ambush by Ottoman artillery (Topçu). Numerous Hungarians were killed in the gunfire, and a general panic set in. The fleeing Hungarian units were driven into the swamps by the advancing Ottomans. 12,000 Hungarians were beheaded. King Ludwig II drowned in the Csele stream (his body was found two months later). A total of 24,000 men fell in this battle, including 4,000 armored riders. The village of Mohács was burned down, peasants who were nearby and all the prisoners were killed as a deterrent. Süleyman reached Buda on September 10, but then withdrew and led more than 100,000 Hungarians into slavery.
Source: Wikipedia