Who is the richest of all time?

Who is the richest man who has ever lived? Think about it a while. From the thousands of years of recorded human history, adjusting for purchasing power, which one individual has accumulated more wealth than any other?

It's not an easy question to answer. I initially had two, somewhat contrary thoughts.

My gut reaction was that it would be today's richest man because modern economies generate unimaginably more wealth than any preceding societies. The likes of Carlos Slim or Bill Gates would surely take the top spot, I thought.

But modern moguls are subject to competition (they should be, at any rate, Mr Slim), taxes, and state intervention. Depending on your political persuasion, these are either the cost of modernity or a sign of our civility. In any case, they limit wealth accumulation.

No, the top of the list will be a conqueror. Only an autocrat with the power of the state could accumulate more wealth than modern billionaires. Perhaps a King of the ancient world; Xerxes or Ramses the second?

The top spot does indeed go to an autocrat but they feature surprisingly sparingly in the top 10. More common are early age capitalists. Perhaps they were best placed benefit from modern economics whilst still under fairly benign governments.

The top five are listed below. Their wealth has been adjusted for inflation and is in today's US dollars. Before you have a look at the list, hazard a guess. Who was the richest man that ever lived?

1. Mansa Musa, US$400bn:Ruler of the Malian empire which provided half the worlds gold and salt in the ancient world
2. The Rothschild Family, US$350bn: Banking
3.  John D Rockefeller, US$340bn: Oil
4. Andrew Carneige, US$310bn: Steel
5. Tzar Nicholas the second, US$300bn: Last Tzar of Russia