Discourses on Fortifications

AND so that the bastions do not turn out acute, it is necessary that at least the enclosure upon which they will have to be built be of six angles, and the more angles it contains, the more perfect the bastions will turn out. It will, therefore, be generally praiseworthy to multiply the angles in circular forms and to avoid the opposite. And when the enclosure is of ten or twelve angles, the enemies, in approaching the fortress, would be wounded from many places. And with greater difficulty could any flank be neutralized from outside the ditches, because whoever attempted to do this would be beaten either by the flank or from behind by the fortress. One must, however, take care not to make more bastions than is necessary, especially when six were enough, so that in such a case one would not lose more in making and maintaining them, both in time of peace and of war, than one would gain in the remainder. And if the enclosure cannot for some reason be entirely circular, let one do the best one can, in such a way that this is held as a rule.

On the flanks. Chapter Four.

NOW, because the principal defense arises from the flanks, since without them one cannot defend the places subject to batteries and assaults, one will have to put great study into making them strong in material and invention, and situating them in a place where they are not easily prevented from doing their duty. Which truly is to defend the enclosures, the ditch, and the counterscarp the outer slope of the ditch of the place that is fortified, although the greater part of that and of this could more difficultly be defended by the flanks, as will be demonstrated later. And to be better understood, I say that until this hour many have made the flanks entirely of masonry, and so that they would come to be less blocked or beaten by the enemies, they not only avoided situating them against eminent places, both on the inside and on the outside, but also made them in the manner that is seen in the plans, A and B. Where they could with reason be called faces rather than flanks, since by straight and by transverse they are seen from the outside, and consequently more beaten or blocked. This does not happen to those that have been made in such a way that they form right angles with the curtains the wall section between two bastions that come between them, because if the enemies wished to do this comfortably, they would be forced to place themselves in the place where the opposite flank is situated. Add to this that, by making one flank opposite to the other, there does not remain in the fortress any part that is not entirely seen by them, even if in the bastions there were no more than one plaza for each, and one embrasure for each flank. And in plan A, besides the imperfection mentioned, it would be necessary to make many embrasures that would uncover by straight, by transverse, up, and down; which, if done, would cause even other damages, which can be considered by practitioners of the art of war.