The Molotov–Ribbentrop Pact signed in August 1939 was a non-aggression agreement between Germany and the Soviet Union. It contained a secret protocol aiming to return Central Europe to the pre–World War I status quo by dividing it between Germany and the Soviet Union. Finland, Estonia, Latvia and Lithuania would return to the Soviet control, while Poland and Romania would be divided. The Eastern Front was also made possible by the German–Soviet Border and Commercial Agreement in which the Soviet Union gave Germany the resources necessary to launch military operations in Eastern Europe.[8]
On 1 September 1939 Germany invaded Poland, starting World War II. On 17 September, the Soviet Union invadedEastern Poland, and, as a result, Poland was partitioned among Germany, the Soviet Union and Lithuania. Soon after that, the Soviet Union demanded significant territorial concessions from Finland, and after Finland rejected Soviet demands, the Soviet Union attacked Finland on 30 November 1939 in what became known as the Winter War – a bitter conflict that resulted in a peace treaty on 13 March 1940, with Finland maintaining its independence but losing its eastern parts in Karelia.[9]
In June 1940 the Soviet Union occupied and illegally annexed the three Baltic states (Estonia, Latvia and Lithuania).[9] The Molotov–Ribbentrop Pact ostensibly provided security to the Soviets in the occupation both of the Baltics and of the north and northeastern regions of Romania (Northern Bukovina and Bessarabia, June–July 1940), although Hitler, in announcing the invasion of the Soviet Union, cited the Soviet annexations of Baltic and Romanian territory as having violated Germany's understanding of the Pact. Moscow partitioned the annexed Romanian territory between the Ukrainian and Moldavian Soviet republics.
