Erik Erikson (1902–1994) is best known for his theory of psychological development, which has its roots in the psychoanalytic importance of identity in personality. His biographies of Gandhi and Martin Luther reveal Erikson's positive view of religion. He considered religions to be important influences in successful personality development because they are the primary way that cultures promote the virtues associated with each stage of life. Religious rituals facilitate this development. Erikson's theory has not benefited from systematic empirical study, but it remains an influential and well-regarded theory in the psychological study of religion.