1) Medieval African kingdoms like Ghana, Mali, and Songhai emerged along the trans-Saharan trade routes in West Africa between the 3rd-16th centuries.
2) They used taxation of the lucrative salt and gold trade to grow wealthy and powerful, developing strong bureaucracies and militaries to control their empires.
3) Rulers like Mansa Musa of Mali transformed cities like Timbuktu into centers of Islamic learning and expanded their empires through effective administration and military conquest.