The war began with the invasion of Poland by Germany and the Soviet Union, followed by the British and French declaration of war on Germany in September 1939. From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, including Poland, Finland, and the Baltic states.…
