How was the Organisation of African Unity formed and why was it formed?

When most African countries got independence from the European colonisers, they observed that one very important thing was for them to be united.
The attempt by some leaders in Africa to create a united organisation was witnessed by divisions. This was mainly based on different affiliations that individual African countries had. There was the affiliations based on colonial orientations, political ideologies and other things.
This brought about the division of African independent countries into three groups. They were Monrovian Group, Casablanca group and Brassaville group.
These groups were focusing on different engagements and interests.
Base on the activities of some African leaders, unity was achieved. This led to the establishment of the Organisation of African Unity on May 25th, 1963.