The Economic Community of West African States (ECOWAS) is a regional organisation of 15 West African countries established on 28 May 1975. Its main goal is the promotion of the economic integration among its members. Indeed, ECOWASis one the five regional pillars of the African Economic Community (AEC). There is an explanation video available below.
Nigeria became a federal republic under the Constitution of 1963 and the monarch and Governor-General were replaced by a ceremonial President. In 1979, under the 1979 Constitution, the President gained executive powers, becoming head of both state and government. There is an explanation video available below.