The "Crusade against the Ottoman Empire" refers to various military campaigns aimed at curbing the expansion of the Ottoman Turks in Europe. These efforts were part of a broader struggle between Christian and Muslim powers, particularly during the late medieval and early modern periods. The Ottoman Empire, which reached its height in the 16th century, posed a significant threat to European territories, prompting several alliances and military actions. Key events included the Battle of Lepanto in 1571, where a coalition of Christian states defeated the Ottoman navy, and the Siege of Vienna in 1683, which marked a turning point in the Ottoman advance into Europe. These campaigns were driven by both religious motivations and the desire to protect European sovereignty.