After the fall of Belgrade in 1521 under Turkish rule, the southeastern borders of Hungary remained unprotected. In order to strengthen his position against the Turks Louis II. Jagel, the Hungarian-Croatian king and king of Bohemia, married Maria of Austria from the Habsburg dynasty in 1522, hoping to gain the help of Habsburg Austria. On the other hand, the Turks interpreted this as a danger to their interests in the Balkans and sought to break the alliance.
However, the situation in Hungary itself was marked by the weakness of the monarchy and the dissatisfaction of the peasantry. After the death of King Matthias Corvinus in 1490, Vladislav II. Jagel, King of Poland and Bohemia came to the vacant Hungarian-Croatian throne. The foreign ruler was without much support in Hungary, which is why he made significant concessions to the nobility, which weakened the royal power and the ability to gather a strong army. In the following decades the nobility used their growing strength to further burden the peasants who reacted with rebellions. In 1514, the Hungarian Parliament promulgated a law that imposed the position of “serf” on the peasants (the population deprived of the freedom to move out of their village). In such conditions, the nobleman could sell together with the land the serfs who lived and worked on it. The situation for the peasants worsened further because the nobility imposed more and more obligations on them to work on noble estates and on the maintenance of fortresses and roads.
The Ottomans offered King Louis various peace offers but he refused them all for two reasons. He believed that the problems of the Turkish threat could only be solved militarily. Also in the case of making peace with the Turks, he feared the military intervention of the Habsburgs from Austria, who also claimed the Hungarian-Croatian throne. All this brought the relationship with the Ottomans to a critical point and in June 1526 Ottoman forces crossed the Danube.
On July 15, 1526, about 70,000 Ottomans under Suleiman the Magnificent occupied Petrovaradin almost without resistance. The situation in Hungary and the unpreparedness of the kingdom for the war, despite the obvious Turkish danger, is sufficiently shown by the fact that from Petrovaradin to Buda (400 km) there was no major fortification that could be used to organize defense.
After Petrovaradin, Ilok was occupied, and then Osijek. The Turks built a large bridge near Osijek and crossed the Drava River at that point and continued north. The king decided to react immediately and placed his army north of Suleiman, near Mohacs along the Danube. At that time, about 13,000 soldiers commanded by Ivan Zapolya guarded the passage through the Southern Carpathians, and due to their distance, it was impossible for them to arrive on time and join the royal army. Also the Croatian count Krsto Frankopan of Ozalj with his 5,000 people from Croatia could not arrive on time.
The total army assembled by King Louis numbered about 30,000 soldiers. About 15,000 infantry and 15,000 cavalry and 50 light cannons. This army was hastily assembled and untrained. Although they were relatively well equipped, they were not ready to oppose the Ottomans, who aspired to a completely different style of warfare than the Europeans. And while the king relied on his well-armored army, 45,000 cavalry (mostly janissaries and spahis) and about 15,000 infantry (of which 10,000 were elite janissaries armed with muskets) marched towards them. They carried about 300 light and heavy cannons with them.
Louis’s generals chose for their position a small hill west of the Danube on a flat swamp battlefield. After the initial cannon fire, the battle was started on the Turkish side by the Rumelia part of their army, and on the right wing they were opposed by Hungarian units led by the Archbishop of Kalocsa Pavao Tomory and caused considerable confusion in the Turkish ranks. Tomory managed to suppress the Turks so much that his soldiers even approached Suleiman’s position who was hit by an arrow in his cuirasse (chest armor). Meanwhile, Turkish cavalry attacked the Hungarian left flank, composed mostly of infantry, with all its might. Although they resisted the Turks with all their might, after a while that side of the Hungarian line gave way and the Ottoman cavalry broke through to other positions of the royal army. At that moment, general chaos ensued and the rest of the Hungarian-Croatian army began to flee the battlefield en masse. In general confusion, the king’s horse slipped in the river Csele, threw him off and the king drowned under the weight of his armor.
The battle lasted just over three hours. About 14,000 Hungarian soldiers were killed (of which about 1,000 nobles) and another 2,000 prisoners were executed after the battle as ordered by Sultan Suleiman. Turkish losses were negligible.
Despite the victory, the Turks failed to conquer all of Hungary but only its central part. Although they broke into Buda in the same year, they soon had to retreat and did not reconquer it until 1541. However, this battle marked the end of the power of the Kingdom of Hungary.
With the death of King Louis II. of Jagel Hungarian-Croatian throne remained empty. Ferdinand I of Habsburg and the powerful Hungarian nobleman Ivan Zapolya appeared as the main candidates. The western part of Hungary and Croatia sided with Ferdinand, while the eastern part (Transylvania) sided with Ivan Zapolya. The struggle for supremacy over the Hungarian crown will last until 1570, when the son of Ivan Zapolya, Ivan Szigismund Zapolya, relinquished his right to the Hungarian throne in favor of the Habsburgs, leaving in turn the Duke of Transylvania.
The difficult wars on Hungarian and Croatian soil that marked the next two centuries after the Battle of Mohács significantly impoverished these areas. They have also encouraged population migrations to the north and west, which will lead to significant population mixing in these war-ravaged areas.