Anschluss
Austria remained part of the Third Reich until the end of World War II, when a provisional government declared the Anschluss null und nichtig (null and void) on April 27 1945. After the war, the Allies occupied Austria, which was recognised and treated as a separate country, but sovereignty was restored only by the Austrian State Treaty and the Austrian Declaration of Neutrality, both in 1955, largely because of the rapid development of the Cold War and disputes between the Soviet Union and its former allies over foreign policy.