The Imperial German Empire began on January 18, 1871, shortly after victory in the Franco-Prussian War (1870-1871). The Unification of Germany, under Otto von Bismarck, occurred when most of the German states gathered together to proclaim King Wilhelm I of Prussia as Kaiser (German Emperor). Austria was a notable exception given the major power shift from the Austro-Prussian War (1866). The German Empire consisted of 26 states, each with their own nobility. There were four Kingdoms: Prussia, Bavaria, Saxony and Württemberg. Six Grand Duchies: Baden, Hessen, Mecklenburg-Schwerin, Mecklenburg-Strelitz, Oldenburg and Saxe-Weimar-Eisenach. Five Duchies: Anhalt, Brunswick, Saxe-Altenburg, Saxe-Coburg and Gotha and Saxe-Meiningen. Seven Principalities: Lippe, Reuss-Gera, Reuss-Greiz, Schaumburg-Lippe, Schwarzburg-Rudolstadt, Schwarzburg-Sondershausen, Waldeck and Pyrmont. Three Free and Hanseatic Cities: Bremen, Hamburg and Lübeck. And one Imperial Territory: Alsace-Lorraine. In 1879, the German Empire consolidated the defensive Dual Alliance with Austria-Hungary. During its 47 years of existence, the German Empire became the industrial, technological, and scientific giant in Europe. By 1913, Germany was the largest economy in Europe. The Empire collapsed after the First World War in the November Revolution (1918-1919) with the abdications of its monarchs and start of the Weimar Republic.