Wilhelmshaven (Hanover) was ceded to Oldenburg. The Prussian lands transferred to Poland after the Treaty of Versailles were reannexed during World War II. Most of the territory was not reintegrated into Prussia but assigned to separate territories of Nazi Germany. Formal dissolution (1945–1947) At the end of World War II in 1945, Germany was divided into Zones of Occupation, and all of Germany east of the Oder–Neisse line was ceded to other countries. As had been the case after World War I, almost all of the territory had been Prussian, although a small portion east of the new border had belonged to Saxony. Most of the land went to Poland, ostensibly as compensation for the seizure of Poland's eastern territories by the Soviet Union. The northern third of East Prussia including Königsberg (renamed Kaliningrad in 1946) was annexed by the Soviets. The losses represented nearly two-fifths of Prussian territory and nearly a quarter of the territory within Germany's pre-1938 borders. An estimated ten million Germans fled or were forcibly expelled from the territories. What remained of Prussia comprised both a little over half of the remaining German territory and a little over half of Prussia's pre-1914 territory. Control Council Law No. 46 of 25 February 1947 explicitly decreed that Prussia should be dissolved. The Allies cited Prussia's history of militarism as a reason for dissolving it. Its reconstitution was also opposed (if not for the same reasons) by powerful German postwar politicians, especially the first West German Chancellor Konrad Adenauer. Moreover, growing tensions between the Western Allies and the Soviet Union eventually resulted in the Prussian territories west of the Oder-Neisse line being further divided by what became known as the inner German border. The lands east of this boundary (except West Berlin) became part of the German Democratic Republic and the remainder became part of the Federal Republic of Germany. This effectively would have made it impossible to reconstitute a Prussian state resembling the one that existed prior to the Nazi era, even if there had been any significant political will to do so. Post-war dismemberment After the Allied occupation of Germany in 1945, the provinces of Prussia were split up into the following territories/German states: Ceded to the Soviet Union The northern third of East Prussia. Today the Kaliningrad Oblast is a Russian exclave between Lithuania and Poland. Ceded to Poland Everything east of the Oder–Neisse line plus