Transylvanian invasion of Hungary (1644–1645)

Background

The Principality of Transylvania was one of the successor states to the medieval Kingdom of Hungary, initially formed in opposition to the Habsburg inheritance of the Hungarian crown. Though autonomous, the principality was under Ottoman vassalage, exerting major influence over their foreign policy. Transylvania was religiously diverse, ruled by Protestant princes. During the outbreak of the Thirty Years War, prince Gabriel Bethlen intervened on the side of the anti-Habsburg rebels multiple times, but then settled with the Habsburgs separately.

In the Peace of Nikolsburg, seven counties in Upper Hungary were ceded to Transylvania for the length of Gábor's reign. In 1630, George I Rákóczi gained the title of Prince over the brother of the deceased Gábor. Rákóczi was also a major landowner in the Hungarian counties neighboring Transylvania, making him an important political player in Royal Hungary as well. Seeking to avoid another conflict, the Habsburgs allowed him to retain these estates and recognised his title as prince.

Throughout the 1630s, there has been negotiation between Sweden, France and Transylvania to re-enter the war but these dragged on without result. Rákóczi's position was also less secure in the eye of the Ottoman Porte than Bethlen's was, making him more wary of securing Ottoman permission before committing himself to a Swedish alliance. Victories by Bernard of Saxe-Weimar in 1638 prompted Rákóczi to dispatch his envoy Johann Heinrich Bisterfeld to Paris.

French Cardinal Richelieu, through Hugo Grotius and Père Joseph, supported the idea of a Transylvanian-Swedish alliance against the Habsburgs. In July 1638, French envoy Du Bois D'Avaugour arrived in Transylvania. Rákóczi demanded Ottoman approval for his departure, protection for his realm, confirmation of his son's succession, neutralization of rival Moses Székely, annual subsidies of 220 000 thalers, and 6000 infantry during the war. Negotiations dragged until late 1639 without resolution, as Rákóczi's demands were deemed excessive.

Despite this, he prepared for war by acquiring munitions: in January 1640, László Ujlaky was sent to Poland for 3000 muskets, 600 Hungarian harnesses, and 359 iron armors.

Campaign of 1644

In early February 1644, Prince Rákóczi began his attack on Royal Hungary, splitting his forces into three groups. He personally commanded the right column toward Székelyhíd, while his son Sigismund moved on Nagykároly in the center, and János Kemény led the left column to Szatmár.

The army included Hajdú fighters and between one and three thousand Ottoman soldiers. The invasion faced little initial opposition, partly because Rákóczi had already placed loyal garrisons in his own forts within Royal Hungary, such as Munkács, Ónod, Sárospatak, and Szerencs. On February 16, he entered Nagykálló and released a manifesto claiming the invasion was a response to Jesuit persecution of Protestants and accusing the Habsburgs of trying to make Hungary a hereditary possession.

Over the next month, several counties—Zemplén, Borsod, Ung, Bereg, Ugocsa, and Abaúj—swore allegiance to him, soon joined by Gömör, Sáros, Szepes, and Torna. Kassa was surrendered without a fight by Ádám Forgách on March 11, and after lengthy talks, Szatmár gave in on March 16, with its garrison switching sides. In late March, the Transylvanian army again advanced west in three columns.

György Kapronczay took 6,000 cavalry north into the Vág valley, while Pál Bornemissza and Gábor Bakos headed for the mining towns in the Garam valley. Rákóczi, his son, and Kemény moved south, besieging Fülek and Léva and setting up headquarters at Drégelypalánk. Ferenc Wesselényi, Fülek’s captain, first claimed neutrality but soon renewed fighting.

By then, however, plans to join forces with Sweden had collapsed because Torstenson was called north to invade Jutland. This freed up Imperial troops in Moravia and Silesia to oppose Rákóczi. Hans Christoph Puchheim led 6,000 soldiers into Hungary, Johann von Götzen brought 8,000, and Esterházy added another 4,000.

Campaign of 1645

In late January 1645, the French envoy Antoine-Fouquet de Marcilly-Croissy met with Rákóczi at Zborov. He explained that France had not known the terms Sweden had agreed to on their behalf, which made them hesitant to cover their promised costs. Still, France was now willing to form a direct pact with Rákóczi to ensure Transylvania stayed in the conflict.

On February 12, Rákóczi convened a council of the estates from the twelve Hungarian counties he controlled. They backed the French alliance. By then, the Ottoman Porte was pushing Rákóczi to accept only seven counties and stop expanding, as the Ottomans were preparing for war with Venice and wanted calm on their Hungarian border.

On March 6, Torstensson defeated the Habsburg army at Jankau, where Götzen died. Sweden urged Rákóczi to move west quickly, but he delayed, failing to take the minor forts of Szendrő and Regéc. Only Kemény advanced a little into Liptó county. Because of this, Torstensson gave up on a direct strike at Vienna and instead besieged Brno.

On April 22, Rákóczi signed a formal alliance with France at Mukachevo. France promised to get the Ottomans to lift their ban, and if that failed, allowed Transylvania to make a separate peace with the Empire. Rákóczi then ordered all his forces, including Kemény's vanguard from the west, to gather at Rakamaz on the Tisza. Puchheim followed him through the Vág valley and then south to Aszaló, but avoided battle.

On May 30, Rákóczi's assembled army began moving west through the Sajó and Rima valleys. The Porte again ordered him to stop, but he ignored this. He captured and burned Fülek, then took Nyitra and Topoľčany.

On July 6, he made contact with the Swedish army: Robert Douglas arrived with 1,800 Swedish cavalry, as agreed in the Swedish-Transylvanian alliance. Rákóczi advanced to Nagyszombat, then sent Sigismund, Kemény, and Gábor Bakos with 14,000 troops to join the Swedish siege at Brno. Shortly after, he crossed into Moravia at Hodonín and reached Ladná on July 27.