She never married. She died in Montreal, Canada, December 10, 1819, of tuberculosis of the lungs. She was noted for her personal beauty and charm and her high intelligence. Quite early she manifested a deep interest in religious mattters and was undoubtedly something of a mystic. Engaged, and apparently sincerely in love, she nevertheless entered a convent, took the vows of a Religious and became a nun. Much has been written about her, including a volume by Sister Helen Morrissey, of the Religious Hospitallers of St. Joseph, the Order to which Fanny Allen belonged.