The Allies of World War II were the countries that opposed the Axis powers during the Second World War (1939-1945). The Allies became involved in World War II either because they had already been invaded or were directly threatened with invasion by the Axis or because they were concerned that the Axis powers would come to control the world. After 1941, the leaders of the United Kingdom, the Union of Soviet Socialist Republics, and the United States of America, known as "The Big Three", held leadership of the Allied powers. France, before its defeat in 1940 and after Operation Overlord in 1944, as well as China were also major Allies. Other Allies included Australia, Belgium, Brazil, Canada, Czechoslovakia, Ethiopia, Greece, India, Mexico, the Netherlands, New Zealand, Norway, the Philippine Commonwealth, Poland, the Union of South Africa, and Yugoslavia.
During December, 1941, U.S. President Franklin Delano Roosevelt devised the name "United Nations (UN)" for the Allies. He referred to The Big Three and China as a "trusteeship of the powerful", and then later "the Four Policemen". The Declaration by United Nations, on 1 January 1942, was the basis of the modern UN. At the Potsdam Conference of July-August 1945, Roosevelt's successor, Harry S. Truman, proposed that the foreign ministers of China, France, the Soviet Union, the United Kingdom and the United States "should draft the peace treaties and boundary settlements of Europe", which led to the creation of the Council of Foreign Ministers.
The alliance was formalised in the Declaration by United Nations on 1 January 1942. There were 26 signatories, as follows:
Australia, Belgium, Republic of China, Canada, Costa Rica, Cuba, Czechoslovakia, Dominican Republic, El Salvador, Greece, Guatemala, Haiti, Honduras, India, Luxembourg, Netherlands, New Zealand, Nicaragua, Norway, Panama, Poland, South Africa, United Kingdom, Union of Soviet Socialist Republics, United States of America, Yugoslavia.
