Former European country; its territory is now part of Germany and Poland. In 1415 it was just the territory in the control of the Hohenzollerns, the rulers of Brandenburg; then over the centuries they added Pomerania, Silesia, East Prussia, the Rhine province, Hanover, and part of Saxony until the Prussian government controlled three-quarters of the German countries of Europe.

Otto von Bismarck became chancellor in 1862 and started working on a goal of complete German unification under the Kaiser's rule. Much of his work toward this goal was done by getting German states to feel they had a common enemy (Denmark, Austria, France). In 1867 the German states formed a confederation but each kept its own government; in 1870, with the Franco-Prussian War about to start, the non-Prussian German states were persuaded to unite with Prussia for their own protection. The complete unification happened in January 1871 when the German Empire was proclaimed under the rule of the Kaiser. Prussia dominated the new state for its first few decades, but this became less and less so as the government changed (Bismarck removed from office by a new Kaiser, and then the eventual change after World War I to a the Weimar Republic rule of Germany).