 Many of the Ottoman–Hungarian Wars (1366–1526) and Ottoman–Habsburg wars (1526–1791) were fought along the river.The most important wars of the Ottoman Empire along the Danube include the Battle of Nicopolis (1396), the Siege of Belgrade (1456), the Battle of Mohács (1526), the first Turkish Siege of Vienna (1529), the Siege of Esztergom (1543), the Long War (1591–1606), the Battle of Vienna (1683), the Great Turkish War (1683–1699), the Crimean War (1853–1856) and the Russo-Turkish War (1877–1878).Along its course, the Danube is a source of drinking water for about 20 million people.