24B THE HISTORY OF MEDIEVAL EUROPE those trying to enter the tower below or to scale its walls. The walls of the castle are also pierced with many narrow slits through which arrows may be shot at the foe. These walls are very thick, especially at the base in order to with- stand battering-rams and support the weight above. In- deed, the castle was something like a modern battleship with its heavy armor plate, its portholes and gun shields, and its turrets. Especial care was taken to protect the entrance to the castle, which was approached by a drawbridge suspended by chains, and which could furthermore be closed in an instant by the portcullis, a heavy grating which was let fall from above like a drop curtain. The gateway might be further protected by flanking towers; and even if the enemy got across the gap left by the lifted drawbridge and broke through the portcullis, they still might find themselves in a small enclosed court or a dark and winding vaulted passage with other doors and barriers yet to force before they were really within the castle precincts proper. Similarly, if the foe gained a footing at some point on the wall, they could not easily rush along the walk on top of the wall to other parts of the castle, since the circuit of the walls was fre- quently interrupted by towers through which one had to make one's way by crooked passages and up steep stairs. Many castles also had subterranean passages of which their defenders could take advantage, but which were unknown to the besiegers. Although a castle might be impressive by its bulk and massiveness, its exterior was plain, rough, and forbidding in appearance. The towers, battlements, and corbels, how- ever, gave considerable variety and picturesqueness. Un- less the castle was large enough to comprise inner courts, upon which windows might safely open and where decora- -tone carving and sculpture could be indulged in with- out fear of its being damaged by stones hurled from cata- pults — unless this was the case, the rooms of the interior were of necessity dark and cold, since they were enclosed by walls several feet thick with only a rare aperture. Often
