Fredericka "Marm" Mandelbaum (March 25, 1825 – February 26, 1894) operated as a criminal fence to many of the street gangs and criminals of New York's underworld, handling between $1–5 million in stolen goods between 1862 and 1884. Like her principal rival John D. Grady and the Grady Gang, she also became a matriarch to the criminal elements of the city and was involved in financing and organizing numerous burglaries and other criminal operations throughout the post-American Civil War era.