Prussia

A historical region and former kingdom of north-central Europe including present-day northern Germany and Poland. Its ancient inhabitants, of Baltic stock, were conquered by the Teutonic Knights in the 13th century. West Prussia was ceded to Poland in 1466, and East Prussia became a Polish fief that passed to Brandenburg in 1618. The kingdom of Prussia was proclaimed in 1701 and was greatly expanded and fortified by Emperor Frederick II (reigned 1740-1786). Prussia was instrumental in the unification of Germany, and in 1871 its king was declared Emperor William I of Germany. The state became a republic in 1918 and was formally abolished after World War II.