How did people go about defending a castle?

Answer by  A36 (629)

Shooting attackers with bows and arrows helped, as did pouring boiling water on people trying to climb the walls. Also the walls were extremely thick.

Answer by  fixitman (80)

Castle defenders had many exciting options! Scalding hot oil or tar was poured down from the parapets and then ignited, crossbow and archer defenders would kill with accuracy from slits dotted about the castle wall and rocks were thrown from above also! The moat was very effective because they would also hide spikes under the water line to stop horsemen.