Born to a wealthy Jewish Pennsylvania family, she had an English mother which meant many trips to London and time in an English school. Her father, a lawyer, was involved in the music scene in Philadelphia and Rosamond grew up meeting many of the conductors, and soloists, of the Philadelphia Orchestra. Sergei Rachmaninoff, Walter Gieseking, Eugene Ormandy, all came to her house, as well as Leopold Stokowsky, Leonard Bernstein and Aaron Copland who became close friends.