This miniature portrait is signed "P. Kramer". There were two miniature painters named Peter Kramer who worked in the United States and it is not clear which of the two painted this portrait. They were Peter Kramer (1823-1907) and Peter Kramer (1857-1941). The former worked in New York and the latter in Philadelphia.
The sitter is named on a attached metal plaque as "William B Astor". William Backhouse Astor was known as "The Landlord of New York". For more about him see William Backhouse Astor . 817