USSR in World War II By amelia.gibson Jan 21, 1924 Vladimir Lenin dies and a troika, including Joseph Stalin, comes into power. Period: Jan 1, 1928 to Dec 31, 1928 Joseph Stalin claims supremacy after eliminating the other members of the troika. Aug 23, 1939 Germany and the USSR signed a secret non-agression pact. This pact divides Poland between the Soviets and the Germans. This pact divides Poland between the Soviets and the Germans. Sep 1, 1939 Germans invade their portion of Poland, beginning World War II. The Polish army was defeated within a few weeks. The Polish army was defeated within a few weeks. Period: Sep 1, 1939 to Dec 2, 1945 World War II Sep 17, 1939 USSR invades eastern Poland, a mere 16 days after the Germans. Nov 30, 1939 Russo-Finnish war begins when the USSR invades Finland. About one million men attacked on several fronts. About one million men attacked on several fronts. Jun 18, 1940 USSR invades the Baltic states, after giving each state an ultimatum of forming a new pro-Soviet government or going to war. Apr 13, 1941 USSR signs neutrality pact with Japan. This was to last for 5 years. Jun 22, 1941 Germany invades Russia. The plan was called Operation Barbossa. Jun 26, 1941 Finland declares war on USSR, initiating the Continuation War. Jun 27, 1941 Hungary and Slovakia declare war on USSR. They then began to contribute to the German invasion of the Soviet Union. Sep 8, 1941 Germany begins the Seige of Leningrad. This occurred as a result of German failure to capture Leningrad. Oct 1, 1941 U.S. begins supplying USSR under the Lend-Lease Act, which was signed by Roosevelt on March 11th, 1941. Oct 16, 1941 USSR evacuates seat of government from Moscow to Kuibyshev, as the Germans advance. Only Stalin stayed in Moscow. Dec 5, 1941 Germany abandons attack on Moscow. Jan 31, 1943 German troops surrender to Soviets at Stalingrad. Nov 28, 1943 Stalin, Roosevelt, and Churchill meet for the first time in Tehran. Feb 22, 1944 USSR bombs Stockholm, Sweden. Feb 26, 1944 USSR bombs Helsinki, Finland. Aug 20, 1944 USSR invades Romania, occupied by the Germans. Aug 23, 1944 Romania surrenders to the USSR, cutting off Germany's last natural oil source. Sep 6, 1944 Bulgaria and Finland surrender to the USSR. Jan 27, 1945 Russians liberate Auschwitz. Feb 4, 1945 Stalin, Roosevelt, and Churchill meet again for the Yalta Conference. Jul 16, 1945 Stalin, Roosevelt, and Churchill meet a final time for the Potsdam Conference. Aug 8, 1945 USSR declares war on Japan.