to hold their dominions more securely, to build fortresses which might serve as a curb and restraint on such as have designs against them, and as a safe refuge against a first onset. I approve this custom, because it has been followed from the earliest times. Nevertheless, in our own days, Messer Niccolo Vitelli thought it prudent to dismantle two fortresses in Citt� di Castello in order to secure that town: and Guido Ubaldo, Duke of Urbino, on returning to his dominions, whence he had been driven by Cesare Borgia, razed to their foundations the fortresses throughout the Dukedom, judging that if these were removed, it would not again be so easily lost. A like course was followed by the Bentivogli on their return to Bologna.

Fortresses, therefore, are useful or no, according to circumstances, and if in one way they benefit,