Liber III, Pars III — Quomodo debent munitiones obsideri, et quomodo periculosius impugnari possunt munitiones obsessae. Cap. XVII.

Liber III, Pars III — Quomodo debent munitiones obsideri, et quomodo periculosius impugnari possunt munitiones obsessae. Cap. XVII.

If the besiegers are negligent and don't fortify themselves diligently, they can be troubled by those who are besieged. For when it happens that sieges can last for a long time, it's not possible for the besiegers to always be equally prepared. Therefore, unless they are fortified, those in the camp (when the besiegers have been occupied with sleep, play, leisure, or some necessity) suddenly break out against them and succeed in taking the tents, dismantling the siege engines, and sometimes many of the besiegers are lost. Therefore, to remain safe, the besiegers should camp far from the besieged fortification, at least to avoid the impact of a projectile or arrow, and they should make ditches around themselves, set up logs there, and build fortifications: so that if the townspeople suddenly want to invade, they would find resistance. Seeing how the besiegers should fortify themselves, so that they are not troubled by the townspeople: it remains to show how many ways they should attack those who are besieged. There is, however, one common and public method of attack, namely, through ballistae, bows, and by throwing stones with hands or slings, and also by the use of ladders. For the industrious in battle, if the besieged make their way to the walls and fortifications, they immediately attack them with ballistae and bows: they throw stones against them with hands or slings; they set ladders against the walls, so that if they can ascend to those parts. Besides these open methods of attack, there is a threefold method of attack not known to all. One way is through tunnels. Another way is by using machines to hurl large and heavy stones. A third method is by using structures pushed up to the walls of the besieged fortifications. So, regarding all these methods of attack, we will first discuss the method using tunnels. First, then, the fortifications are undermined through tunnels, which are underground passages. The besiegers should dig privately in some location: before that place, they should set up a tent or some other structure to prevent the besieged from seeing where they begin to dig; for by making underground passages, as those who mine for silver do when they find veins of metal, they should proceed through those passages, making them deeper than the trenches of the fortification to be conquered, until they reach the walls of the aforementioned fortification; if this can be done, it is easy to capture the fortification. For this reason, first they must dig the walls and place timber there so that they do not fall immediately. And when they have undermined all the walls, or the majority of the walls, if the besiegers see that they can capture the fortification simply by the collapse of the walls, they should immediately set fire to the timber supporting the walls and cause all the walls or a large part of them to fall, and fill the trenches: so that at the same time (as if by an unexpected event) the besieged are terrified, making it easier to conquer the town. It's also important to note that underground passages must always be reinforced with boards and other supports, so that the earth doesn't collapse and suffocate those digging: the earth that is removed from these trenches should be hidden in such a way that it can't be seen by those inside the fortifications. And again, when fire is applied to the supporting timbers of the wall, those who are placing the fire and those with them should flee to a safe place, so they aren't harmed by the collapse of the walls. Thus, it should be done in the attack through tunnels, since the mere collapse of the walls is sufficient to capture the fortification. However, when it is believed that this is not enough, with the walls already undermined and propped up, fire should not yet be applied, but one must proceed to greater fortifications and larger walls of the castle or besieged city, and through similar underground passages, so that access can be gained to the city and castle: all of this can be done secretly without being noticed by those inside the fortifications, although it can still be done without difficulty and over a long period of time. Therefore, once these things are accomplished during some nighttime period, or at another suitable time for fighting, the application of fire should be made, so that the walls and undermined fortifications collapse at the same time: and through the underground passages, access should be made to the castle or city: and through the entrance created by the falling walls, the remaining attackers can enter the castle or besieged city: and thus they will be able to capture it.