Spoiler alert: It’s not Jeff Bezos or Elon Musk.

You may have never heard of him, but Mansa Musa of Mali is considered by many to have been the richest man in the history of the world. Stanford’s History Education Group has put together a fantastic collection of primary sources to allow students to explore Mansa Masa’s pilgrimage to Mecca and the impressions that his lavish gifts made on the communities through which he traveled. Boston University has also published some educational resources on Mansa Musa and John Greene has covered Mansa Musa in his popular Crash Course World History series. I use these resources in my own world history classes, and students always enjoy not only learning about Mansa Musa and his wealth, but also contrasting the medieval Islamic world with medieval Europe and considering the challenges historians face when trying to understand people and time periods that have left us with few reliable written records.