Allies of World War II

The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during the Second World War (1939–1945) to oppose the Axis powers, led by Nazi Germany, the Empire of Japan, and the Kingdom of Italy. Its principal members by the end of 1941 were the United Kingdom, United States, Soviet Union, and China. Membership in the Allies varied during the course of the war. When the conflict broke out on 1 September 1939, the Allied coalition consisted of the United Kingdom, France, and Poland, as well as their respective dependencies, such as British India. They were soon joined by the independent dominions of the British Commonwealth: Canada, Australia, New Zealand and South Africa. Consequently, the initial alliance resembled that of the First World War. As Axis forces began invading northern Europe and the Balkans, the Allies added the Netherlands, Belgium, Norway, Greece, and Yugoslavia. The Soviet Union, which initially had a nonaggression pact with Germany and participated in its invasion of Poland, joined the Allies after the German invasion of the Soviet Union in June 1941. The United States, while providing some materiel support to European Allies since September 1940, remained formally neutral until the Japanese bombing of Pearl Harbor in December 1941, after which it declared war and officially joined the Allies. China had already been at war with Japan since 1937, and formally joined the Allies in December 1941. The Allies were led by the so-called "Big Three"—the United Kingdom, the Soviet Union, and the United States—which were the principal contributors of manpower, resources, and strategy, each playing a key role in achieving victory. A series of conferences between Allied leaders, diplomats, and military officials gradually shaped the makeup of the alliance, the direction of the war, and ultimately the postwar international order. Relations between the United Kingdom and the United States were especially close, with their bilateral Atlantic Charter forming the groundwork of their alliance.