When an attacking force laid siege to a castle, they used techniques and weapons not unlike those developed by the ancient Romans. First they surrounded the castle in order to cut off all avenues of escape and resupply. They also built a camp ringed by ditches and palisades to secure their own position. Then they built siege engines—great stonethrowing devices—which they hoped would break down the castle walls. Although the knights’ chivalric code gave pride of place in warfare to a charge on horseback with lance or to hand-to-hand combat with swords, military engineers skilled in the mechanics of offensive engines had to first break through the walls. To breach the walls the army used battering rams, various kinds of projectiles, and mines. In other words they tried to go through, over, or under the walls (Document 25).