Final answer:
The medieval West African empires of Ghana and Mali engaged in wide-ranging trans-Saharan trade with North Africa, Europe, and the Middle East, dealing in gold, salt, and a variety of other commodities. Gao served as an important trade link, and the wealth of Mali's ruler Mansa Musa was well known to European explorers such as the Portuguese.
Step-by-step explanation:
The medieval empires of Ghana and Mali were significant players in the trans-Saharan trade. Ghana's wealth was largely derived from its abundant gold resources and active trade across North Africa, connecting to markets in the Mediterranean, Europe, the Near East, and beyond. Similarly, the Mali Empire prospered through its control of the same trans-Saharan trade routes, facilitating the exchange of gold, salt, and other commodities with regions such as the Middle East.
The strategic location of the trading city of Gao as an important link in trans-Saharan trade network was inherited by successive empires, leading up to the expansion of the Songhai kingdom. Present-day Ghana, known during the colonial era as the "Gold Coast," continues to reflect the historical significance of gold in the region's economic development.