On August 23, the Soviets demanded that Finland cede territories near Leningrad and a military base at Hango, for which they offered Finland alternative territory. On November 30, 1939, after the negotiations failed, the Soviet Union launched the "Winter War." Despite the unequal balance of forces, the Finnish put up stiff military resistance. On March 12, 1940, the countries concluded a peace treaty in which the Soviet demands were met.
Practically speaking, the stipulation that Finland would fall within the Soviet sphere of influence was part of the secret appendix to the Ribbentrop-Molotov agreement that partitioned such spheres between Nazi Germany and the Soviet Union.
