1. Powerful kingdoms emerged in West Africa due to the trans-Saharan salt-gold trade. Kingdoms like Ghana and Mali grew wealthy from taxing this trade and controlling the gold mines of West Africa.
2. Trading city-states emerged in East Africa due to their access to the Indian Ocean trade routes. Cities like Kilwa grew rich exporting goods like gold, ivory, and slaves to Arabia, India, and beyond.
3. Cultural diffusion spread between Africa, the Middle East, and Asia along these trade routes. Islam spread significantly and great cities like Timbuktu became centers of Islamic learning.