Officially, the United Nations was not formed until October 1945. Events during World War II (1939–45), however, had paved the way for the founding of the international peacekeeping organization that today is familiar to people around the world.
In 1939 Nazi German führer (supreme leader) Adolf Hitler (1889–1945) and his troops invaded Poland, and soon Germany had conquered much of Europe. Leaders of nine nations—Belgium, Czechoslovakia, France, Greece, Luxembourg, the Netherlands, Norway, Poland, and Yugoslavia—met with Great Britain and its Commonwealth states (countries that belonged to the British Empire) in London, England. On June 12, 1941, the countries signed the Inter-Allied Declaration, vowing to work together for a free world. Two months later, on August 14, U.S. President Franklin Delano Roosevelt (1882–1945) and British prime minister Winston Churchill (1874–1965) signed the Atlantic Charter, in which they outlined their aims for peace.
On January 1, 1942, the "Declaration by the United Nations" was signed by twenty-six countries who pledged to work together to fight the Axis powers (Germany, Italy, and Japan) and they agreed not to make peace separately. The term United Nations, also known as the UN, is believed to have originated with Roosevelt.
In late 1943 the major Allied leaders (called the Big Three)—Roosevelt, Churchill, and Soviet premier Joseph Stalin (1879–1953)—met in Teheran, Iran, for the first time during the war. They agreed on the responsibility of a United Nations organization in keeping the peace once the war was over. Though ending the war was foremost in their minds, the leaders had seen two world wars fought in close succession and were determined that the nations of the world could work together to prevent such an event from happening again. In August 1944, at the Dumbarton Oaks Conference in Washington, D.C., representatives of Britain, the United States, the Soviet Union, and China met to make plans for a peacekeeping organization. The outcome of the meeting, which lasted into October, was the basic concept for the UN Security Council: the world's major powers would have permanent seats on the council and a limited and rotating membership beyond that.
When the Big Three met again at the Yalta Conference in the Soviet Union in February 1945, they discussed matters that were central to ending the fighting with Germany and with Japan. Roosevelt, Churchill, and Stalin also announced that a conference of the United Nations would open in San Francisco on April 25 of that year. On June 26, 1945, the governing treaty of the United Nations was signed by the delegates. On October 24, 1945, shortly after the war ended with Japan (the war with Germany ended in May), the United Nations officially came into existence when the required number of nations approved the charter. At that time, fifty nations were members of the UN.
Further Information: Thakur, Ramesh Chandra, ed. Past Imperfect, Future Uncertain: The United Nations at Fifty. New York: St. Martin's Press, 1998; United Nations Home Page. [Online] Available http://www.un.org/, October 26, 2000; "United Nations." The Columbia Encyclopedia: Sixth Edition. [Online] Available http://www.bartleby.com/65/un/UN.html, Octobers 26, 2000.