They made the curtain walls much higher, added the imposing gatehouse and inserted an ingenious ‘sally port’ – a secure secret doorway – so defenders could sneak out in an emergency.
Gall codi'r llawr i osod pilen sy'n gwrthsefyll lleithder, er enghraifft, orfodi lleithder i fynd i mewn i'r waliau lle gall achosi problemau mwy difrifol o bosibl.