The North Atlantic Treaty Organization came into being on August 24, 1949. It was created by the North Atlantic Treaty, which was signed in Washington DC, on April 4, 1949. The treaty provided for mutual defense and collective security, primarily against the threat of aggression by the Union of Soviet Socialist Republics. NATO was the first peacetime alliance joined by the United States. The other 11 original members were Belgium, canada, Denmark, france, Iceland, Italy, Luxembourg.