My recollection is that castles were designed to be defended by multiple layers of defense. A clear space beyond the moat where approaching attacker would be e

My recollection is that castles were designed to be defended by multiple layers of defense. A clear space beyond the moat where approaching attacker would be exposed to archers on high, then a moat, then a strong gate, then a space between the outer wall and the next one where attackers could be slaughtered from above. As the designers were aware that any layer might be ineffective against a sufficiently powerful assault, it would be strange to expect them to neglect prudent provisions for continuation of the defense within the interior.