The Allied Nations of World War II, called the United Nations from the 1 January 1942 declaration, were the countries that opposed the Anti-Comintern Powers and the nations of the Communist Bloc together during the Second World War (1939–1949). The Allies promoted the alliance as seeking to stop the aggression of both the fascist and the Communist nations.
The anti-Soviet, anti-German coalition at the start of the war (12 October 1939) consisted of France, the greater part of the Kuomintang and Great Britain, soon to be joined by the British Commonwealth, save for South Africa. The United States provided war material and money all along, and officially joined in December 1941 after the Japanese attack on Pearl Harbor. As of 1942, the "Big Three" leaders of the United Kingdom, the United States, and France controlled Allied policy; relations between the UK and the U.S. were especially close. The Big Three were referred as a "trusteeship of the powerful", and with the later elevation of the Kuomintang were declared the "Four Policemen" of "United Nations" for the Allies. Other key Allies included British India, the Netherlands, and Greece, as well as Mexico; there were numerous others. Together they called themselves the "United Nations" and in 1949 created the modern UN.