The Battle of Vienna took place at Kahlenberg Mountain near Vienna on 12 September 1683 after the 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 Polish–Lithuanian Commonwealth, both under the command of Polish King John III Sobieski, against the Ottomans and their vassal and tributary states. The battle was won by the combined forces of the Holy Roman Empire and the Polish–Lithuanian Commonwealth, marking the beginning of their military cooperation against the Ottomans.