Mansa Musa and the Empire of Mali
The West African empire of Mali, successor to Ghana, controlled the gold that minted much of the medieval world's money — and its emperor Mansa Musa may have been the richest person in all of history. On a legendary 1324 pilgrimage to Mecca, he handed out so much gold in Cairo that he wrecked the region's economy for years. His city of Timbuktu became a fabled center of Islamic scholarship, its libraries holding hundreds of thousands of manuscripts.
The path or medium of exchange moves, and a place or power rises or declines because it sits on or off the new route.