The North Atlantic Treaty, signed in Washington on 4 April 1949, created an alliance of ten European and two North American independent nations committed to each other's defence.Four more European nations joined the Alliance between 1952 and 1982, bringing the number of members to 16. The admission of Czech Republic, Hungary and Poland on March 12, 1999 brought the number of members to 19.
NATO's members are Belgium, Canada, Czech Republic, Denmark, France, Germany, Greece, Hungary, Iceland, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Spain, Turkey, United Kingdom and the United States.