Ottoman Siege of Vienna

In the autumn of 1529, an Ottoman army led by Sultan Suleiman the Magnificent besieged Vienna, the capital of the Austrian Habsburg lands, and failed to take it. The siege lasted only a few weeks, but it marked the farthest point the Ottomans reached into central Europe in the sixteenth century and became a powerful symbol in European memory of a Christian city holding firm against an Islamic empire.

The background lay in the collapse of Hungary. In 1526 Suleiman crushed the Hungarian army at the Battle of Mohács, and King Louis II died in the retreat. The vacant throne was claimed by two rivals: Ferdinand of Habsburg, brother of Emperor Charles V, and the Hungarian nobleman John Zápolya. Zápolya turned to the Ottomans for support and became Suleiman's vassal. When Ferdinand took Buda in 1527, he gave the sultan both a pretext and an opportunity to intervene again.

Suleiman set out in the spring of 1529 with a very large force, though its exact size is uncertain and contemporary figures vary widely. Heavy rain reportedly slowed the march, and much of the artillery was bogged down or left behind. The army reached Vienna in late September, by which time the city's defenders had strengthened its medieval walls and gathered a garrison of perhaps some ten to twenty thousand men, including German and Spanish troops, under the veteran commander Nicholas, Count of Salm. Ottoman forces tried bombardment, mining and assaults, but the defenders countered tunnels and repelled attacks. Supplies ran short, disease and cold set in, and the campaign season was ending.

In mid-October Suleiman ordered a withdrawal after a final unsuccessful assault. The retreat through bad weather was costly. Historians still debate how far the failure reflected Vienna's resistance and how far it reflected the logistical limits of campaigning so far from Constantinople. Suleiman may also have regarded the expedition mainly as a show of force to establish Zápolya's position and challenge the Habsburgs, rather than a bid for permanent conquest.

The consequences were mixed. The Ottomans kept most of Hungary's central plains and returned in 1532, though that campaign stalled at the small fortress of Kőszeg. In 1541 they annexed Buda directly, beginning roughly a century and a half of Ottoman rule in much of Hungary. Vienna itself stayed Habsburg, and it became the frontier bastion of Central Europe. It was besieged again in 1683, when a relief army broke the siege and the long Ottoman retreat from the region began.