How rich is "Rich"? 

There’s rich. There’s starting quarterback rich. And then there’s founder-of-Facebook rich.

But when you’re talking about the richest person ever, you have to go all the way to Timbuktu in the 14th century.

CelebrityNetWorth.com has assembled a list of the 25 richest people who ever lived, adjusted for inflation.

Topping the list is Mansa Musa I, ruler of the Malian Empire until 1337. His net worth of $400 billion was amassed through his empire’s production of more than half of the world’s supply of gold and salt.

Many of the others on the list will be more familiar. Interesting.