A relief army arrived on the hills above Vienna just as the city was about to fall

In 1683 an Ottoman army of up to 300,000 besieged Vienna for two months, undermining its walls with tunnels of gunpowder. On 12 September, a relief force led by Poland's King John III Sobieski charged down from the surrounding hills in one of history's largest cavalry charges, shattering the siege in a single afternoon and ending the Ottoman Empire's westward expansion into Europe.

— Andrew Wheatcroft, The Enemy at the Gate: Habsburgs, Ottomans, and the Battle for Europe — Basic Books, 2008
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