Prussia (German: Preußen) was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg and centered on the region of Prussia. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organised and effective army. Prussia shaped the history of Germany, with its capital in Berlin after 1451. In 1871, German states united in creating the German Empire under Prussian leadership. In November 1918, the monarchies were abolished and the nobility lost its political power. Prussia was effectively abolished in 1932, and officially abolished in 1947.
The name Prussia derives from the Old Prussians. In the 13th century, German crusaders, the Teutonic Knights, conquered “Old Prussia”. In 1308 the Teutonic Knights conquered the formerly Polish region of Pomerelia with Gdańsk (Danzig). Their monastic state was mostly Germanised through immigration from central and western Germany and in the south, it was Polonised by settlers from Masovia. The Second Peace of Thorn (1466) split Prussia into the western Royal Prussia, a province of Poland, and the eastern part, from 1525 called the Duchy of Prussia, a fief of the Crown of Poland up to 1657. The union of Brandenburg and the Duchy of Prussia in 1618 led to the proclamation of the Kingdom of Prussia in 1701.
Prussia entered the ranks of the great powers shortly after becoming a kingdom, and exercised most influence in the 18th and 19th centuries. During the 18th century it had a major say in many international affairs under the reign of Frederick the Great. During the 19th century, Chancellor Otto von Bismarck united the German principalities into a “Lesser Germany” which excluded the Austrian Empire.
At the Congress of Vienna (1814–15), which redrew the map of Europe following Napoleon’s defeat, Prussia acquired a large section of north western Germany, including the coal-rich Ruhr. The country then grew rapidly in influence economically and politically, and became the core of the North German Confederation in 1867, and then of the German Empire in 1871. The Kingdom of Prussia was now so large and so dominant in the new Germany that Junkers and other Prussian élites identified more and more as Germans and less as Prussians.
The Kingdom ended in 1918. In the Weimar Republic the state of Prussia lost nearly all of its legal and political importance by 1932. The old Prussian élites played a passive role in the Nazi regime; Prussia was legally abolished in the 1940s. East Prussia lost all of its German population after 1945, as Poland and the Soviet Union absorbed its territory.
The term “Prussian” has often been used, especially outside of Germany, to emphasise the professionalism, aggressiveness, militarism and conservatism of the Junker class of landed aristocrats in the East who dominated first Prussia and then the German Empire before 1918.