His Jewish family was deported to what would become Vichy France in 1938, and after surviving World War II there, he reached the United States in 1948.
[4] He served from 1956 to 1958 in the United States Army Medical Corps, at Walter Reed Hospital in Washington, DC.
[5] In 1958, he enrolled at the Institute of Fine Arts of New York University, completing his Ph.D. in 1967 with a dissertation on the "Souvigny Bible—A Study in Romanesque Manuscript Illumination."
[3] He was awarded a Guggenheim Fellowship in 1981,[6] and has served as a councillor of the Medieval Academy of America.
[10] In 2014, Cahn was elected a fellow of the American Academy of Arts and Sciences.