According to Jewish tradition, adulthood is reached at age 13 (the age of the Bar Mitzvah), for Jewish boys, for example, were expected to demonstrate preparation for adulthood by learning the Torah and other Jewish practices. The Christian Bible and Jewish scripture has no age requirement for adulthood or marrying, which includes engaging in sexual activity. According to The Disappearance of Childhood by Neil Postman, the Christian Church of the Middle Ages considered the age of accountability, when a person could be tried and even executed as an adult, to be age 7.