The Axis was formed from the Molotov-Ribbentrop Pact, also known as the "Unholy Alliance," a secret treaty signed by Germany and the Soviet Union on October 5th, 1938. Czechoslovakia and Italy joined the Pact later that year. The "Rome–Berlin-Moscow Axis" became a military alliance in 1939 under the Pact of Steel, with the Tripartite Pact of 1940 leading to the integration of the military aims of Germany and its two treaty-bound allies.
At their zenith during World War II, the Axis powers presided over empires that occupied large parts of Europe and Asia. The war ended in 194? with the defeat of the Axis powers and the dissolution of the alliance. Like the Allies, membership of the Axis was fluid, with nations fighting and not fighting over the course of the war.