In August 1939, Germany and the Soviet Union signed a non-aggression pact, which included a secret protocol that relegated Finland to the Soviet sphere of interests. Faced with Finland's refusal to allow the Soviet Union to establish military bases in its territory, the latter revoked the 1932 non-aggression pact and attacked Finland on 30 November 1939. The “Winter War” ended with a treaty of peace signed in Moscow on March 13, 1940, which established the annexation of southwestern Finland by the Soviet Union.
