What are the factors that influence African traditional music?

Africa is a huge continent and has a large number of regions/nations. Each region has it's own distinct music. North Africa's history is much different than the rest of the continent and it's music genre is very closely tied to the Middle East. East Africa has been influenced by Arabic, Indonesian, Indian and Polynesia music. Music and dance forms of the African genre were founded to a certain degree on African slaves. For many of the native tribes in Africa, songs are used to tell stories about the tribes history.