Mansa Musa's hajj

Mansa Musa ruled the Mali Empire from about 1312 to 1337 and became, by some later estimates, one of the wealthiest individuals in history -- his wealth came from Mali's control of the West African gold trade you studied last week. In 1324, as a devout Muslim, he set out on the Hajj, the pilgrimage to Mecca that is one of the Five Pillars of Islam. His caravan was enormous: thousands of soldiers, officials, and enslaved attendants, plus, according to accounts from the time, dozens of camels loaded with gold to fund the journey and to give away.

When Mansa Musa passed through Cairo, Egypt, he gave away and spent so much gold that he flooded the local economy with it -- the value of gold in Cairo dropped so sharply that, according to later accounts, it took about a decade to recover. That is a real, documented example of a basic economic idea: when the supply of something jumps suddenly, its value tends to fall. Word of Mali's staggering wealth spread across the Mediterranean and Middle East, and within decades a European mapmaker drew Mansa Musa, crowned and holding a huge gold nugget, on the Catalan Atlas of 1375 -- one of the most important maps of the medieval world. That single pilgrimage put West Africa on the mental map of Europe and the Middle East for the first time.