A new study has produced an inflation-adjusted list of the richest people of all time. To give you an idea of just how rich the rich people on the list are consider that Sam Walton and Warren Buffett are the poorest guys to make the cut.

The richest person in history, according to the study, was Mansa Musa I of Mali—an obscure 14th century African king. Musa, who made his fortune on salt and gold, would have an inflation-adjusted fortune of $400 billion. Mali likely benefited from cronyism and a mand economy, but many of the others on the list made their wealth through free enterprise. Indeed, entrepreneurs crowd out emperors; out of the top 25 men (and they are all men), 14 are American businessmen.

What is most interesting about the list, though, is how much we benefit from the products and services created by these wealthy men. From cars puters (Henry Ford and Bill Gates) to cheap consumer goods and toilet paper (Sam Walton and Friedrich Weyerhaeuser), we are better off because of the innovations and inventions that made these men wealthy. They got rich by improving the lives of millions (or billions) and contributing to the economic growth of the world.

The fruits of this economic growth are often worth more than their weight in gold—or in Musa’s case, salt and gold. The price to replace the American middle class living standard most of have now is almost incalculable. Who would trade their 21st forts in order to be the ruler of the Malian empire? Not me. Even to convince me to move back to the 1970s—an era before iPhones, , and central air conditioning—you’d have to promise me a minimum e of $10 million dollars.

Such is the magic of free enterprise. Not only does it make some people extraordinarily wealthy, it makes the rest of us extraordinarily better off too.