The origin of the North Atlantic Treaty Organization (NATO) lies in the signing of the Washington Treaty of 1949 by which twelve countries from both sides of the Atlantic pledged to defend each other in the event of an attack on any of them. It currently has 29 member countries, 21 partners for cooperation in the Euro-Atlantic Partnership Council (EAPC), seven in the Mediterranean Dialogue, four countries participating in the Istanbul Cooperation Initiative (ICE) and nine partners around the world. Spain became the 16th member of NATO on 30 May 1982.