When they took over the Mali Empire, they inherited a large collection of book knowledge, which could possibly have been half a billion or even more.
The Songhai Empire could possibly have been even better than Mali. They had complex urbanization, complex security surveillance, and impressive knowledge for education. When they took over the Mali Empire, they inherited a large collection of book knowledge, which could possibly have been half a billion or even more. Knowledge from aphrodisiacs to space and time is well documented.