NATO is a military alliance of twenty-eight European and two North American countries that constitutes a system of collective defense. The process of joining the alliance is governed by Article 10 of the North Atlantic Treaty, which allows for the invitation of "other European States" only and by subsequent agreements. Countries wishing to join must meet certain requirements and complete a multi-step process involving political dialog and military integration. The accession process is overseen by the North Atlantic Council, NATO's governing body. NATO was formed in 1949 with twelve founding members and has added new members eight times. The first additions were Greece and Turkey in 1952. In May 1955, West Germany joined NATO, which was one of the conditions agreed to as part of the end of