when did the soviets join the allies in wwii
The invasion of Poland on 1 September 1939, started the war in Europe, and the United Kingdom and France declared war on Germany on 3 September. Poland fielded the third biggest army among the European Allies, after the Soviet Union and United Kingdom, but before France.oland was a minor factor after its defeat in 1939; France was a minor factor after its defeat in 1940. After first having cooperated with Germany in partitioning Poland whilst remaining neutral in the Allied-Axis conflict, the Soviet Union perforce joined the Allies in June 1941 after being invaded by Germany.