Military confrontations with an expanding Ottoman Empire were a major foreign political challenge not only for the Austrian Habsburgs but also for the Holy Roman Empire as a whole. Since the early sixteenth century, the Ottoman Turks had repeatedly advanced into the Balkans toward Central Europe. By the early 1680s, the Muslim power, allied with France, had wrested Hungary from Habsburg control, and in July 1683, roughly 150,000 Ottoman troops laid siege to Vienna, the capital of the Holy Roman Empire. It was the second time that Ottoman forces besieged the city, the first attack having come in 1529. This time around, however, they came closer to achieving their goal of taking the city. They captured Vienna’s outer fortifications and started making serious inroads into its defenses. In one of the most dramatic episodes in its history, Vienna held out for two months but eventually ran out of supplies and manpower. The approximately 12,000 troops who defended the city during the siege were outnumbered by Ottoman forces by more than 10:1. This oil painting by Franz Geffels (1625-94) shows the city under siege.