Leopold I (name in full: Leopold Ignaz Joseph Balthasar Felician; Hungarian: I. Lipót; 9 June 1640 – 5 May 1705) was Holy Roman Emperor, King of Hungary and Croatia, King of Bohemia and King of Serbia. The second son of Ferdinand III, Holy Roman Emperor, by his first wife, Maria Anna of Spain, Leopold became heir apparent in 1654 by the death of his elder brother Ferdinand IV. Elected Holy Roman Emperor in 1658, Leopold would rule as such until his death in 1705.
Leopold's reign is known for the conflicts with the Ottoman Empire in the east, and the rivalry with Louis XIV, a contemporary and first cousin, in the west. After more than a decade of warfare, Leopold emerged victorious from the Great Turkish War thanks to military talents of Prince Eugene of Savoy. By the Treaty of Karlowitz, Leopold recovered almost all of the Kingdom of Hungary which had fallen under the Turkish yoke in the years after the 1526 Battle of Mohács.
Leopold fought three wars against France – the Dutch War, the Nine Years' War, and the War of the Spanish Succession. In this last, Leopold sought to give his younger son the entire Spanish inheritance, disregarding the late Spanish king's will. To this end, he started a war which soon engulfed much of Europe. The early years of the war went fairly well for Austria, with victories at Schellenberg and Blenheim. But this was a stubborn war that would drag on till 1714, nine years after Leopold's death which, in truth, barely had an effect on the warring nations of Europe. When peace returned at the end of it all, Austria could not be said to have emerged as triumphant as it did from the war against the Turks.