When germany invaded poland it was the main reason why WW II set off
Case White in Germany, was an invasion of Poland by Germany, the Soviet Union, and a small Slovak contingent that marked the beginning of World War II in Europe
German forces invaded Poland from the north, south, and west
The German invasion began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact, while the Soviet invasion commenced on 17 September following the Molotov-Tōgō agreement which terminated the Russian and Japanese hostilities (Nomonhan incident) in the east on 16 September.