Axis refers to alliances formed among Germany, Italy, and Japan before and during World War II (1939-1945). In 1936, Italy and Germany joined together in an alliance called the Rome-Berlin Axis. The term Axis was used to suggest that all Europe rotated about a line between these two capitals. Japan joined the alliance in 1940, and the alliance became the Rome-Berlin-Tokyo Axis. Bulgaria, Hungary, Romania, and the German-created states of Croatia and Slovakia became Axis satellites. The inability of the major Axis powers to forge an effective alliance helped the Allies win World War II.