Liber III, Pars III — Quomodo munierendae sunt civitates, et castra et universaliter omnes munitiones, ut ab obsidentibus difficilius capiantur. Cap. XXI.

Liber III, Pars III — Quomodo munierendae sunt civitates, et castra et universaliter omnes munitiones, ut ab obsidentibus difficilius capiantur. Cap. XXI.

It's not enough to know how fortifications should be built and what kind of walls they should have, and how they should be situated, unless you also understand how they should be defended so that they can't be easily conquered. As mentioned above, there are three ways to conquer fortifications: namely, through hunger, thirst, and combat. Therefore, fortifications under siege must be properly defended. So that they cannot be conquered by any of these methods. To avoid being conquered by hunger, three things must be considered: namely, that grains, oats, barley, and all kinds of food that can serve for sustenance should be brought to the besieged fortification before it is besieged by outsiders; and if there is fear of a siege before the harvest of crops, such supplies should be acquired from nearby places, so that the besieged fortification does not suffer from a lack of food. Moreover, anything that cannot be brought to the fortification (or if it could be brought but would not be very useful to the besieged city or castle) should be burned; so that the besiegers do not gain any advantage from it, and that the besieged do not have to fight with their own resources. If there is concern about the duration of the siege, so that it may last for a long time, the city or castle under siege should be fortified with millet: for millet, among other grains, rots less and is said to last longer. Moreover, the supply of salted meats should not be overlooked. A large supply of salt is also very useful for a besieged fortification because it serves many purposes. Secondly, when fortifying a castle or city under siege, it’s not only important to ensure a large supply of provisions is brought to the besieged fortification, but also that the delivered provisions are distributed through careful and temperate providers among the families. Therefore, if the besieged fortification is large and cannot recover provisions from elsewhere, the provisions must be brought to the public granaries in every part of the city, and distributed temperately through capable men. If the besieged fortification has a modest perimeter, achieving this is not difficult, for indeed, much preparation of provisions is pointless unless they are distributed sparingly and with moderation. Thirdly, it must be considered that weak and useless individuals, who are not able to contribute to the defense of the besieged fortification, should be sent to other parts, if it can be done conveniently; for they consume and eat what should be given to the warriors. Again, if there is a fear of a shortage of provisions, the animals that are in the besieged fortification, from which the besieged can conveniently abstain, should be killed and eaten, or salted if they are suitable for food; indeed, in such a case, many things should be eaten that common usage forbids. When considering how the besieged fortification survives, it must be noted how the besieged should behave to avoid being overcome by hunger. For before anyone besieges them, they must ensure that they go to such a fortification where there is a supply of water; but if there are no springs there, they should dig wells; and if the place is so dry that no water can be found, cisterns should be built so that the abundance of heavenly waters can supply the deficiency of other waters. If a besieged fortification is near the sea and cannot have fresh water except from a spring, because it has sweet water, which the besiegers prevent them from accessing, then it can be sweetened with wax. For according to the philosopher in the Meteorology, whatever salty water passes through the pores of wax is turned entirely into sweet water. It is also necessary to bring a large supply of vinegar and wine to the besieged fortification, so that the soldiers do not become so weakened by drinking only water that they cannot resist the besiegers bravely; as has been shown, there are remedies to be applied against hunger and thirst through which the besieged fortification has been accustomed to endure: it remains to see what remedies should be applied so that the besieged fortification is not overcome in battle. Therefore, a large supply of sulfur, pitch, and oil should also be brought to the city or besieged castle to burn the enemy's machines. Iron and wood should be brought in sufficient quantity to the besieged fortification, so that wooden spears can be made. And also the arrows and other necessary buildings can be made for the fortification. Through iron, weapons can also be repaired, and spears and arrows can be made, and other things through which they can defend themselves against the besiegers. There is also a great abundance of iron that is very useful to those besieged for destroying the buildings and machines of their besiegers, as will appear in the following chapter. Stones from the torrents should also be transported in large quantities to the fortifications, because they are sturdier and more suitable for throwing. From these, the walls and towers of the besieged fortifications should be rebuilt. Pulverized lime should also be brought to the fortifications in large quantities, and from it, many vessels should be prepared; so that when the besiegers approach the walls of the fortifications, those vessels should be thrown, which, when broken, will let the dust enter the eyes of the besiegers, and so annoy them that they may be struck as if blind and unable to see. A supply of ropes and sinews is also useful for the besieged fortifications, for the ballistae, bows, and other preparations; if the sinews fail, horsehair or women's hair can be used in their place. Vegetius recounts that when the Romans ran short of sinews and could not repair their machines, the Roman women, having cut off their hair, gave it to their husbands: through whom, with the machines repaired, they repelled the attack of their enemies. For they preferred (as Vegetius says) to live with their husbands with disfigured heads than to serve the enemy with their hair intact. There are also horns of beasts to be transported to the fortifications for repairing ballistae and bows, and raw hides for covering machines and other buildings, so that they are not burned by the enemy through fire. With these precautions and through the means mentioned, the besieged will be able to resist; so that their fortifications are not overcome in battle by the besiegers.