11. John of Gaunt Peak fortune: $101 billion
Source of wealth: Richard II’s regent during much of the latter’s rule and the father of Henry Bolingbroke (who would eventually come back from exile to depose Richard and take the English throne into his hands). One of Shakespeare’s meekest characters.
12. A.T. Stewart Peak fortune: $88.9 billion
Source of wealth: An American entrepreneur, he founded the first department store in lower Manhattan and subsequently expanded his retail business.
13. Frederick Weyerhaeuser Peak fortune: $79.4 billion
Source of wealth: He founded Weyerhaeuser Company, one of the biggest timber companies in the United States, after he arrived to America from Germany in the 19th century.
14. Henry Duke of Lancaster Peak fortune: $77.5 billion
Source of wealth: English diplomat, noble, soldier, and founding member of the Order of the Garter.. He is remembered today for his peace talks with France and for being a patron of Corpus Christi College, Cambridge
15. Carlos Slim Peak fortune: $74.5 billion
Source of wealth: Many. He is most famous, however, for having big holdings in major telecom companies, especially America Movil, one of the largest corporations in Latin America.
16. Jay Gould Peak fortune: $71.2
Source of wealth: Railroad baron and gold speculator, Jay Gould masterminded the 19th century transportation boom in America. He and financier James Fisk also bought up a dominating share of the gold market at the time – enough to directly affect market movements during Gould’s lifetime.
17. Stephen Van Rensselaer Peak fortune: $68.5
Source of wealth: Major of the US Militia and member of the New York State Assembly, Rensselaer was also heir to one of the most well-endowed estates in the US. He founded the Rensselaer Polytechnic Institute with a portion of his wealth.
18. Marshall Field Peak fortune: $66.1 billion
Source of wealth: He started the retail store chain Marshall Field and Co. in Chicago during the Civil War.
19. Sam Walton Peak fortune: $64.5 billion
Source of wealth: Founded Walmart in 1962 and lived a famously humble life. As Walmart keeps growing, Walton’s four children have individual fortunes around $20 billion each.
20. Warren Buffett Peak fortune: $63.9 billion
Source of wealth: Investments. The Oracle of Omaha joined Berkshire Hathaway as chairman in 1970 and hasn’t looked back. He has pledged to give away 99 percent of his money.