Matthias' reforms did not survive the turbulent decades that followed his death in 1490. An oligarchy of quarrelsome magnates gained control of Hungary. Not wanting another heavy-handed king, they procured the accession of Vladislaus II, the king of Bohemia and son of Casimir IV of Poland, precisely because of his notorious weakness: he was known as King Dobže, or Dobzse (meaning "all right"), from his habit of accepting, without question, every petition and document laid before him.

Vladislaus II also abolished the taxes that had supported Matthias' mercenary army. As a result, the king's army dispersed just as the Turks were threatening Hungary. The magnates also dismantled Mathias' administration and antagonized the lesser nobles. When Vladislaus II died in 1516, his ten-year-old son Louis II became king, but a royal council appointed by the Diet ruled the country. Hungary was in a state of near anarchy under the magnates' rule. The king's finances were a shambles; he borrowed to meet his household expenses despite the fact that they totaled about one-third of the national income. The country's defenses sagged as border guards went unpaid, fortresses fell into disrepair, and initiatives to increase taxes to reinforce defenses were stifled. In August 1526, the Ottomans under Suleiman appeared in southern Hungary, and he marched nearly 100,000 Turkish-Islamic troops into Hungary's heartland. The Hungarian army, numbering around 26,000, met the Turks at Mohács. Though the Hungarian troops were well-equipped and well-trained, they lacked a good military leader, while reinforcements from Croatia and Transylvania did not arrive in time. They were utterly defeated, with up to 20,000 killed on the field, while Louis himself died when he fell from his horse into a bog. After Louis's death, the rival factions of Hungarian nobles simultaneously elected two kings, John Zápolya and Ferdinand of Habsburg. Turks seized the opportunity, conquering the city of Buda and then partitioning the country in 1541.