Discourses on Fortifications

of the time besieged as would be required. And wishing to attempt this, they need many people due to the inequality and ruggedness of the valleys, who, not being able to stay united in the way that would be necessary, it happens that each part of the army could perhaps not relieve the other with the necessary speed. And as for the labors and expenses, the choice of mountains is better in many things; because when there is no lack of terrain, one can more expeditiously prepare the enclosures of the fortress, not having need of large and regal defenses in every part. Rather, the greater part of them can be secured with small flanks and with little height of trenches, nor is it necessary in many parts to make earthen ramparts, because nature itself has provided them, so that the expenses are greatly diminished. And especially since they rarely have need of very large squares, as also of ditches, embankments, or any kind of cavalier, because these are most of the time provided by the place itself, or are not necessary, wherefore the labor and the inconvenience to the enemies are multiplied. And if it happens that those inside need to retreat, they will be able to do so with more advantage, being able to be in a more elevated place. And besides this, if, through the inadvertence of the one who governs, some mine were to be made by the adversaries, the ascent tends to prove much more difficult.

In the mountains, on the other hand, a man cannot make a choice of the shape that he likes best, but it is necessary that he adapt the figure of the fortress to the site in such a manner that at times he will be forced to encompass more land than necessity requires, or, due to not being able to widen it, the fortress will be entirely or partially defective. Besides this, with a large enclosure, one usually encloses very little square space. Mountains also tend to have a scarcity of water, and many times, due to rains, they receive much damage, both because the soil of the mountain does not tend to be as good as that of the plain, and also because the water that falls, running precipitously from the summit of the mountains, tends, upon exiting from the designated places, to ruin through its exit some part of the enclosure, which cannot be done without much time, labor, and expense, due to the difficulty of transporting the necessary things there to build and equip it. And that which can be the cause of the greatest inconvenience is that, besides the mountains being at times subject to mines and ovens, the enemies can also many times, and from many parts, approach without being discovered, and particularly through the valleys, by which they are for the most part surrounded; they come to be subject to plots and sudden assaults, especially when the fortress does not have ditches around it, or the enclosure is not as high as is appropriate.

Fortresses in the sea on rocks or similar places, and distant from the mainland by no less than a hundred canne an Italian unit of measurement, roughly 2 meters, are not subject to heavy batteries and are little or not at all subject to assaults, mines, hoes, and similar instruments, and also to sieges, because it cannot be forbidden for them to be relieved, and consequently they will not have need of great provisions, nor of great and royal defenses. And where there is no port, provided that a pier could be built, one could keep armed vessels there for one's own defense and to harass and occupy the things of others, and also to make the place mercantile with the industries that might be introduced there. And besides that such places do not have to fear armies on land, they can also care little for those at sea, both for the stated reasons and because rare are those who have, or can place, a large fleet at sea.

What the sea brings of bad is that that fortress which is far out inside it cannot serve as a frontier on the mainland, both because transit is not always granted and because one cannot go out with cavalry and do what might be necessary.

The fortress placed on the shore of the sea, or partly inside it, even if it comes to be as secure on every side as if it were entirely inside the water and far from the mainland, will nonetheless enjoy many of the said benefits of the sea, and one will be able to make more use of the conveniences that the land tends to provide. And the enemy, to besiege it and take it by storm, will almost always be forced to have a double army, one by sea and the other by land, or to make one so powerful by sea that it can bring horses, munitions, and every other necessary thing. And because those who can do this are rare, one could say that every time such a fortress was well made, it would serve as a frontier, both from the land side and from the sea side, because one could constrain the enemy there not to pass further, so as not to leave the fortress at his back. And wishing to take it by storm, for the aforementioned reasons, it would perhaps be impossible. Furthermore, with part of the said fortress secured by the sea, the enclosure can be made more capable, and therefore in time of peace and of war, it could be defended with fewer men and less expense than those on the mainland. It will be necessary, however, to take care that in this particular instance I do not intend to speak of those fortresses that have some strip of mainland, which, by the enemy, could quite easily, according to the diversity of the methods that can be used, be enclosed and hindered.

The fortress that shares the mainland is subject to armies on land, and to an enemy who, no matter how far away he stays, provided he has a fleet at sea with which he could put men on land and fight the fortress, which comes to be even more subject to corsairs, since they could not only cause trouble for the vessels that might be sailing for diverse occurrences, but also damage the land in many ways, when however one does not