Salomon was born on 9 October 1852 in Mobile Alabama, the son of Rosalie Alice Salomon and her husband David Salomon (1820-1875), at that time a dealer in cotton, and great-grandson of early Polish-Jewish settler Haym M. Salomon who died in Philadelphia in 1785 and was one of the financiers for the American Revolution. He was married to Helen Forbes Lewis. Salomon was for years a member of the banking firm of Speyer & Co. and in 1902 established in New York the banking firm of William Salomon & Co. He was also chairman of the board of the Baltimore & Ohio Railroad. He lived at 1020 Fifth Avenue, New York. He died in New York on 14 December 1919.
Salomon bought fifteen early Italian paintings through Duveen Brothers just before he died, but in May 1921 his heirs had decided to sell them at auction. These were to be a great embarrassment to Duveen as many of the pictures were of doubtful attribution.
In the archives of Knoedler & Co., New York, is a letter from Muller-Ury dated May 3, 1921 in which he requests that the shipping clerk come to his studio to collect this picture and to bring the same to Mr. Elisha Walker, c/o Blair & Co., 24 Broadway, New York, and to charge him for expressing it. Blair and Co. took over Salomon & Co, shortly after Salomon’s death in April 1920. Elisha Walker and Blair & Co were two of the executors of Salomon’s estate. Muller-Ury almost certainly painted his portrait from a photograph.
After many vicissitudes, Blair & Co, which incorporated Salomon’s company, closed for business in 1970, and it is unknown what happened to the company’s portraits which may well have included Muller-Ury’s.