Reign of Ulaszlo II and Louis II

Matyas's reforms did not survive the turbulent decades that followed his reign. An oligarchy of quarrelsome magnates gained control of Hungary. They crowned a docile king, Vladislav Jagiello (the Jagiellonian king of Bohemia, who was known in Hungary as Ulaszlo II, 1490-1516), only on condition that he abolish the taxes that had supported Matyas's mercenary army. As a result, the king's army dispersed just as the Turks were threatening Hungary. The magnates also dismantled Matyas's administration and antagonized the lesser nobles. In 1492 the Diet limited the serfs' freedom of movement and expanded their obligations. Rural discontent boiled over in 1514 when well-armed peasants (if they are in rebellion they are not really acting as serfs) under Gyorgy Dozsa rose up and attacked estates across Hungary. United by a common threat, the magnates and lesser nobles eventually crushed the rebels. Dozsa and other rebel leaders were executed in a most brutal manner.

Shocked by the peasant revolt, the Diet of 1514 passed laws that condemned the serfs to eternal bondage and increased their work obligations. Corporal punishment became widespread, and one noble even branded his serfs like livestock. The legal scholar Stephen Werboczy included the new laws in his Tripartitum of 1514, which made up Hungary's legal corpus until the revolution of 1848. The Tripartitum gave Hungary's king and nobles, or magnates, equal shares of power: the nobles recognized the king as superior, but in turn the nobles had the power to elect the king. The Tripartitum also freed the nobles from taxation, obligated them to serve in the military only in a defensive war, and made them immune from arbitrary arrest. The new laws weakened Hungary by deepening the rift between the nobles and the peasantry just as the Turks prepared to invade the country.

When Ulaszlo II died in 1516, his ten-year-old son Louis II (1516-26) 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 1521 Sultan Suleyman the Magnificent recognized Hungary's weakness and seized Belgrade in preparation for an attack on Hungary. In August 1526, he marched more than 100,000 troops into Hungary's heartland, and at Mohacs they cut down all but several hundred of the 25,000 ill-equipped soldiers whom Louis II had been able to muster for the country's defense. Louis himself died, thrown from a horse into a bog.

After Louis's death, rival factions of Hungarian nobles simultaneously elected two kings, Janos Zapolyai (1526-40) and Ferdinand (1526-64). Each claimed sovereignty over the entire country but lacked sufficient forces to eliminate his rival. Zapolyai, a Hungarian and the military governor of Transylvania, was recognized by the sultan and was supported mostly by lesser nobles opposed to new foreign kings. Ferdinand, the first Habsburg to occupy the Hungarian throne, drew support from magnates in western Hungary who hoped he could convince his brother, Holy Roman Emperor Charles V, to expel the Turks. In 1538 George Martinuzzi, Zapolyai's adviser, arranged a treaty between the rivals that would have made Ferdinand sole monarch upon the death of the then-childless Zapolyai. The deal collapsed when Zapolyai married and fathered a son. Violence erupted, and the Turks seized the opportunity, conquering the city of Buda and then partitioning the country in 1541.