Germany is today a federal republic consisting of sixteen states. Federalism has a long tradition in German history. The Holy Roman Empire comprised many petty states, numbering more than 300 around 1796. The number of territories was greatly reduced during the Napoleonic Wars (1796?1814). After the Congress of Vienna (1815), 39 states formed the German Confederation. The Confederation was dissolved after the Austro-Prussian War. Prussia and the other states in Northern and Central Germany united as a federal state, the North German Federation, on July 1, 1867. The Southern states Bavaria, Württemberg, Baden and Hesse-Darmstadt entered military alliances with Prussia. In the Franco-Prussian War of 1870?71, those states joined the North German Federation. It was consequently renamed to German Empire, and the parliament and Federal Council decided to give the Prussian king the title of German Emperor. The new German Empire included 25 states and the imperial territory of Alsace-Lorraine. After the territorial losses of the Treaty of Versailles, the remaining states continued as republics of a new German federation. These states were gradually de facto abolished and reduced to provinces under the Nazi regime. The creation of the Federal Republic of Germany in 1949 was through the unification of the western states (which were previously under American, British, and French administration) created in the aftermath of World War II.