Nathan Markus Oppenheim (1810-1891)

He was the senior partner of N.M Oppenheim & Co., Diamond and Pearl dealers. He was witty and outgoing which aided his business, but handed down some dubious advice to his grandson, Felix Warburg: "to sell a man pearls that you have got and he wants, that is not business. To sell a man pearls that you have not got and he does not want, that is business".