The Ghana Empire, known to its own people as Wagadou, was the first of the great Sahelian trading states of West Africa — a Soninke-ruled power that grew rich not by mining gold but by taxing the trans-Saharan exchange of West African gold for Saharan salt, making 'Ghana' a byword for gold in the medieval Mediterranean before it gave way to its successor, Mali.
First, a warning that prevents a common confusion. The medieval Ghana Empire was not in the country called Ghana today. It rose far to the northwest, in lands that are now southern Mauritania and western Mali, and it had already declined for centuries before the modern nation borrowed its name in 1957. The old empire's people did not even call it Ghana. That was a title for their king, which Arab traders heard and applied to the whole realm. They called their country Wagadou. And its real achievement was not gold in the ground. It was a state clever enough to sit between the gold and the salt and tax everything that crossed.