The North Atlantic Treaty Organization (NATO) was a peacetime military alliance that consisted of twelve nations. These nations included; Belgium, Canada, Denmark, France, Great Britain, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, and the United States. These nations all agreed that "an armed attack against one or more of them in Europe or North America shall be considered an attack against them all." Then in May 1949, all of those nations agreed to the creation of the Federal Republic of Germany (West Germany). It later joined NATO in 1955. This is significant because it caused the Soviet Union to create the Warsaw Pact. This caused the Cold War to be institutionalized throughout a massive division of the continent.