It was formed on April 4, 1962 from the 15 protected states of the Federation of Arab Emirates of the South. On January 18, 1963 it was merged with the British Colony of Aden. On June 1964, the Upper Aulaqi Sultanate was added for a total of 17 states. The remaining four British-protected Arab states that known as the Protectorate of South Arabia was joined the Federation on January 1, 1968. The South Arabian Federation gained its independence on October 23, 1971 and became a member of the Commonwealth Confederation.