Liber III, Pars III — Quomodo per aedificia lignea impulsa ad muros civitatis, et castri, impugnari possint munitiones obsessae. Cap. XIX.

Liber III, Pars III — Quomodo per aedificia lignea impulsa ad muros civitatis, et castri, impugnari possint munitiones obsessae. Cap. XIX.

There are three ways to attack besieged fortifications. One method involves tunnels, while another uses stone-throwing machines. The third method employs wooden structures that are pushed against the walls of the besieged fortification. Therefore, having discussed the attack methods using tunnels and stone-throwing machines, we now turn to the method involving wooden structures pushed against the walls or fortifications of a besieged castle or city. Such wooden structures can be classified into four types. These include battering rams, vine-like structures, towers, and shelters. The battering ram, known as the 'testudo', is a wooden structure covered with raw hides to prevent it from being burned. Under this testudo, a beam is placed, strongly constructed to prevent being crushed by stones, and it has a very hard front for striking. This type of beam is secured with ropes or iron chains to a wooden tortoise, and it hides itself like a ram: afterward, it strikes and breaks down the walls of the besieged fortification with great force. For when the wall is struck by such a beam, it is hit many times, to the point that the stones in it begin to shift; at its head, a certain iron piece is driven in, shaped like a sickle, through which the shaken and battered stones are pulled out from the wall, so that it can be pierced more quickly. This kind of structure is useful for attacking a fortification, especially when someone cannot reach its walls. For if the fortifications cannot be taken by rams or tortoises, the dimensions of the walls of that fortification must be measured, and according to those dimensions, or even taller, wooden towers or camps must be constructed, which should be covered with raw hides so they are not consumed by fire. With these wooden camps, the besieged fortifications are attacked in two ways. First, by throwing stones. For if the height of the camps exceeds the height of the walls, and also of the towers and battlements that are on them, those in the camps will be in a position somewhat like those in the fortifications, just as those in the fortifications are to those who are below or on the ground. Moreover, this structure is covered with raw hides, so that they cannot be harmed by fire. Such a structure is typically built to be eight feet wide and sixteen feet long, and its height is equal to the number of men who can stand inside it comfortably. For this type of structure, whether of such size or even larger, it should be well fortified all around and pushed against the walls of the besieged fortification; under it, men can dig into those walls. This structure is useful when the besieged fortification is such that it can be pushed against its walls. The third type of structures includes towers or camps. For if the fortifications cannot be taken either by battering rams or by siege towers, the measurements of the walls of that fortification must be taken, and according to those measurements, or even according to a higher standard, wooden towers or camps should be constructed, which must be covered with raw hides so they aren't burned by fire. With these wooden camps, the besieged fortifications are attacked in two ways. First, by throwing stones. For if the height of the camps exceeds the height of the walls, and also the heights of the existing towers and battlements: then those in the camps will be positioned in relation to those in the fortifications in such a way that those in the fortifications are like those who are in the low ground or on the earth. In such camps, they set up sloping bridges through which they can reach the walls of the besieged fortification. The height of the walls can be understood in two ways. First, by means of a shadow. For a light thread, whose length is known, must be tied to an arrow and shot up to the walls of the fortification according to the length of the shadow that can be determined: at that moment when the length of the shadow is measured, a piece of wood must be raised high, casting a shadow of that length; and according to the height of that wood, the height of the walls will be. However, since the sun does not always shine and cast a shadow, but sometimes is hidden by clouds, we will provide another method for measuring the height of any building and any walls. Let a piece of wood or a board be taken, and let it be laid on the ground: and let the aforementioned board be placed at its feet, and let it be observed from the top of that board: and if the sight proceeds higher than the building whose height is to be measured, let it be drawn closer to that building; but if the sight extends lower, with the board being at its feet and lying on the ground, let it be moved away from the aforementioned building until the top of the board exactly aligns with its height. For, as can be geometrically proven, the distance from the head of a person lying in such a position to that building will equal the height of the building. Measurements of such heights can also be taken using the rules provided in the Astrolabe and the Quadrant. But we shouldn't worry about this: it's enough to say as much about these matters as is necessary for our purpose. The fourth type of buildings are called 'Muscles.' These are small structures under which men can hide while pulling or pushing the camp up to the walls of the besieged fortification. However, through such muscles, the camp can be almost continuously brought up to the besieged fortification: once this is done, the fortification must be attacked in three ways. For in a castle built in this way to attack the fortification, three things must be considered: namely, the upper part exceeding the walls; and the sections of the fortification that need to be taken, which are the middle part to which the falling bridges are applied over those walls; and the lower part, to which the muscles are applied, from which men are pulling or pushing the camp. When the castle approaches as much as it should to the walls of the besieged fortification, those who are in the upper part should throw stones and drive away those who are on the walls. But those who are in the middle part should lower the bridges and invade the walls. However, those who are in the lower part and under the muscles, if they can, should pay attention to the walls and undermine them, so that even those besieging can enter the besieged fortification. There are also ballistae, bows, stone-throwing machines, and all such things that should be gathered together so that when these are to be made, they can strike the fortification. For the more ways the fortification is attacked at once, the more the besieged are frightened, and the faster it is captured.