 The Kingdom of Prussia became the leading state of the German Empire after its creation in 1871.However, the Treaty of Versailles following World War I granted West Prussia to Poland and made East Prussia an exclave of Weimar Germany (the new Polish Corridor separated East Prussia from the rest of Germany), while the Memel Territory was detached and annexed by Lithuania in 1923.Following Nazi Germany's defeat in World War II in 1945, war-torn East Prussia was divided at Joseph Stalin's insistence between the Soviet Union (the Kaliningrad Oblast became part of the Russian SFSR, and the constituent counties of the Klaipėda Region in the Lithuanian SSR) and the People's Republic of Poland (the Warmian-Masurian Voivodeship).