Sobieski’s relief broke the 1683 Ottoman siege of Vienna
On 12 September 1683, after two months of Ottoman siege, Holy Roman and Polish–Lithuanian armies under King John III Sobieski smashed the attackers at Kahlenberg Mountain. Historians often call it a turning point after one hundred fifty years of tension since 1529.
Ernst Rüdiger von Starhemberg held the garrison for Emperor Leopold I while Sobieski commanded the relief; the Lithuanian contingent arrived late, only after the city had been freed. Ottoman manpower figures swing from roughly ninety thousand up toward three hundred thousand; papers found in Kara Mustafa’s tent put the opening host near one hundred seventy thousand when the siege began mid-July.
Vienna controlled Danube and overland routes toward Germany and the eastern Mediterranean, a long Ottoman prize. The empire backed Hungarian rebels against Habsburg Counter-Reformation policy; clashes with Imre Thököly helped Grand Vizier Kara Mustafa persuade Sultan Mehmed to authorize the push. Kara Mustafa spent years preparing, repairing roads and bridges toward imperial territory and stockpiling cannon and ammunition in the Balkans. Vienna had not faced an Ottoman threat since the 1566 siege of Szigetvár halted Suleiman the Magnificent, and plague had swept the city in 1679. In 1681 the Ottomans sent troops to Thököly's anti-Habsburg Kuruc rebels, recognised him as king of Upper Hungary, and even promised the Hungarians a Kingdom of Vienna, despite twenty years of formal peace under the Treaty of Vasvár.
Allied victory opened sustained Habsburg–Polish cooperation against the Ottomans and, some argue, ended serious Ottoman bids to take Vienna. The day also saw what is reckoned the largest cavalry charge ever recorded.
The consequences were lasting. The Ottomans took no further territory in Europe and never threatened Vienna again, and in the war that dragged on until 1699 most of Ottoman Hungary passed to Emperor Leopold I.
Source: Battle of Vienna
