On August 28, 1526, at the Battle of Mohács, in a decisive battle the Hungarian Empire was conquered by the Ottoman Empire led by Suleiman the Magnificent. From the article:was
"Battle of Mohacs | Summary
Mohács
In order to expand the Ottoman Empire into the heart of Europe, Süleyman would have to conquer the kingdom of Hungary. The first stage to accomplishing this goal was the capture of Belgrade in 1521. Süleyman could then use Serbian territory to launch an invasion.
The Hungarians knew that an attack was coming but could not win any support from other Christian powers. Süleyman’s army made an uncontested crossing of the Drava River on a pontoon bride, which took five days, while King Louis waited to face the invaders on a large marshy plain at Mohacs. The Hungarians intended to rely upon the shock effect of their charging armored knights, but Süleyman had better balanced forces, including infantry Janissaries armed with arquebuses, sipahi light cavalry, and formidable banks of cannon.
The charge of the Hungarian cavalry caused serious casualties to the Ottoman vanguard, but Süleyman’s elite Janissaries pushed back the Hungarians, who were also torn apart by Turkish cannon fire. As the Hungarians fell back, they were outflanked and encircled by the fastmoving Ottoman light cavalry. The Hungarian force was annihilated. King Louis of Hungary was thrown from his horse and killed as he tried to escape the carnage. Süleyman proceeded into Buda (September 10) but then withdrew from the country, taking more than 100,000 captives with him.
The defeat at Mohacs was a disaster that ended the existence of Hungary as an independent united kingdom . A prolonged civil war (1526-38) ultimately resulted in the incorporation of the central and southern two-thirds of Hungary into the Ottoman Empire (1547) and in the establishment of Transylvania and the eastern Hungarian provinces as an autonomous principality within the Ottoman Empire.
Losses: Ottoman, 2,000 of 60,000; Hungarian, 18,000 of 35,000."