Africa as a whole has a population of 1.3 billion and has a gdp of $2.6 trillion. With unlimited natural resources Oil,Gas,Gold,Diamond,Silver etc.
While a country like Japan with a population of 123 million and has a GDP of $5 trillion. It has no significant natural resources.
https://asadullahali.files.wordpress.com/2012/10/ibn_khaldun-al_muqaddimah.pdf - english translation
He made some comments regarding the Somali people;
"On the western shore of the Indian Ocean is Zayla' (Zila'), which is on the boundary of Abyssinia, and the desert...