Austro-Ottoman War: Battle of Vienna: Several European armies join forces to defeat the Ottoman Empire.

The Battle of Vienna took place at Kahlenberg Mountain near Vienna on 12 September 1683 after the imperial city had been besieged by the Ottoman Empire for two months. The battle was fought by the Holy Roman Empire (led by the Habsburg monarchy and the PolishLithuanian Commonwealth, both under the command of King John III Sobieski) against the Ottomans and their vassal and tributary states. The battle marked the first time the Commonwealth and the Holy Roman Empire had cooperated militarily against the Ottomans, and it is often seen as a turning point in history, after which "the Ottoman Turks ceased to be a menace to the Christian world". In the ensuing war that lasted until 1699, the Ottomans lost almost all of Hungary to the Holy Roman Emperor Leopold I.The battle was won by the combined forces of the Holy Roman Empire and the PolishLithuanian Commonwealth, the latter represented only by the forces of the Crown of the Kingdom of Poland (the march of the Lithuanian army was delayed, and they reached Vienna after it had been relieved). The Viennese garrison was led by Feldzeugmeister of the Imperial Army (Holy Roman Empire) Ernst Rdiger Graf von Starhemberg, an Austrian subject of Holy Roman Emperor Leopold I. The overall command was held by the senior leader, the king of Poland, John III Sobieski, who led the relief forces.

The opposing military forces were those of the Ottoman Empire and its vassal states, commanded by Grand Vizier Merzifonlu Kara Mustafa Pasha. The Ottoman army numbered approximately 90,000 to 300,000 men (according to documents on the order of battle found in Kara Mustafa's tent, initial strength at the start of the campaign was 170,000 men). They began the siege on 14 July 1683. Ottoman forces consisted, among other units, of 60 ortas of Janissaries (12,000 men paper-strength) with an observation army of some 70,000 men watching the countryside. The decisive battle took place on 12 September, after the arrival of the united relief army.

Historians maintain that the battle marked the turning point in the OttomanHabsburg wars, a 300-year struggle between the Holy Roman and Ottoman Empires. During the 16 years following the battle, the Austrian Habsburgs gradually recovered and dominated southern Hungary and Transylvania, which was largely cleared of Ottoman forces. The battle is noted for including the largest known cavalry charge in history.

The Great Turkish War (German: Großer Türkenkrieg), also called the Wars of the Holy League (Turkish: Kutsal İttifak Savaşları), was a series of conflicts between the Ottoman Empire and the Holy League consisting of the Holy Roman Empire, Poland-Lithuania, Venice, Russia, and Habsburg Hungary. Intensive fighting began in 1683 and ended with the signing of the Treaty of Karlowitz in 1699. The war was a defeat for the Ottoman Empire, which for the first time lost large amounts of territory, in Hungary and the Polish–Lithuanian Commonwealth, as well as part of the western Balkans. The war was significant also by being the first time that Russia was involved in an alliance with Western Europe.

The war largely overlapped with the Nine Years' War (1688–1697), which took up the vast majority of the Habsburgs' attention while it was active. In 1695, for instance, the Holy Roman Empire states had 280,000 troops in the field, with England, the Dutch Republic, and Spain contributing another 156,000 specifically to the conflict against France. Of those 280,000, only 74,000, or about one quarter, were positioned against the Turks; the rest were fighting France. Overall, from 1683 to 1699, the Imperial states had on average 88,100 men fighting the Turks, while from 1689 to 1697, they had on average 127,410 fighting the French.