To maintain the social system of the city, it was necessary to have a force ready to oppose any uprising of the helots (that occurred several times in the classical period). To ensure their military readiness, Spartiate youths enrolled in military training (agoge) from the age of seven to thirty, the age of full citizenship. From that age until they became too old to fight, they would live in their barracks, visiting their families (and, later, their wives) only when they could sneak out. Spartiate women, as well, were expected to remain athletically fit since the Spartans believed that strong and healthy parents would produce strong and healthy children.