When one desired to attack the enemy's castle, there was a variety of ways one could go about the process. If the structure was only made of timber, the job was relatively easy. It could be battered, burnt, or bored through with a terebrus or teretrus. If, however, the lord had had the foresight to use stone construction, the walls of the curtains and towers were generally impervious to most assault tactics until the advent of artillery warfare.
The heel of the Achilles was used for mining under a castle. Although useless against castles built on a foundation of rock or an island, mining was especially effective by using the weight of the stones against the enemy.…