Since time immemorial, there have been only three real ways to make a fortune – take it, build it, or grow it.
History is littered with examples of conquest and occupation for financial gain and some ancient royal and military figures feature highly among the richest of all time.
SEE THE LIST: History's richest businessmen
Assuming that’s not a reliable strategy, we can turn to the other two ways to amass wealth.
When you look back through the last few centuries, it’s staggering how frequently massive wealth comes with the birth of a new industry – oil, steel, retail, software, and telecommunications featuring highly.
Trying to compare fortunes across time is a little like comparing sports people from different generations – you can try to make allowances for relative differences like inflation, GDP, currency – but it’s necessarily subjective.
Obviously many also lost fortunes or gave money to charity, so picking the right value to use is also tough.
All of that said, these six men stand undisputedly among the richest of all time.
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Scott Phillips is an investment analyst with The Motley Fool. He owns shares in Telstra and Berkshire Hathaway. You can follow Scott on Twitter @TMFGilla. Take Stock is The Motley Fool Australia’s free investing newsletter. Packed with stock ideas and investing advice, it is essential reading for anyone looking to build and grow their wealth in the years ahead. Click here now to request your free subscription, whilst it’s still available. This article contains general investment advice only (under AFSL 400691).