The wealth of Mansa Musa the King of Mali is immeasurable. Musa became ruler of the Mali Empire in 1312, taking the throne after his predecessor, Abu-Bakr II, for whom he’d served as deputy, went missing on a voyage he took by sea to find the edge of the Atlantic Ocean. Musa’s rule came at a time when European nations were struggling due to raging civil wars and a lack of resources. During that period, the Mali Empire flourished thanks to ample natural resources like gold and salt.

And under the rule of Musa, the prosperous empire grew to span a sizeable portion of West Africa, from the Atlantic coast to the inland trading hub of Timbuktu and parts of the Sahara Desert. As the territory grew while Musa was on the throne, so did the economic standing of its citizens.

He made his fortune by exploiting his country’s salt and gold production. Many mosques he built as a young man still stand today. After Mansa Musa I death in 1331, however, his heirs were unable to hang on to the fortune, and it was substantially depleted by civil wars and invading armies.