Marie Catherine Sophie, Comtesse d'Agoult, was a French romantic author who published using the pen name Daniel Stern. She divorced her first husband, Charles Louis Constant, Comte d'Agoult in August 1835, and lived with virtuoso pianist and composer Franz Liszt from 1835 to 1839.Marie Catherine Sophie, Comtesse d'Agoult, was a French romantic author who published using the pen name Daniel Stern. She divorced her first husband, Charles Louis Constant, Comte d'Agoult in August 1835, and lived with virtuoso pianist and composer Franz Liszt from 1835 to 1839....more