https://www.britannica.com/place/Prussia
Prussia, German Preussen, Polish Prusy, in European history, any of certain areas of eastern and central Europe, respectively (1) the land of the Prussians on the southeastern coast of the Baltic Sea, which came under Polish and German rule in the Middle Ages, (2) the kingdom ruled from 1701 by the German Hohenzollern dynasty, including Prussia and Brandenburg, with Berlin as …