The Prince by Niccolo Machiavelli Chapter 20 Page 4

the hands of his own soldiers who have served under him in his ancient dominions.

Our forefathers, even such among them as were esteemed wise, were wont to say that ‘Pistoja was to be held by feuds, and Pisa by fortresses,’ and on this principle used to promote dissensions in various subject towns with a view to retain them with less effort. At a time when Italy was in some measure in equilibrium, this may have been a prudent course to follow; but at the present day it seems impossible to recommend it as a general rule of policy. For I do not believe that divisions purposely caused can ever lead to good; on the contrary, when an enemy approaches, divided cities are lost at once, for the weaker faction will always side with the invader, and the other will not be able to stand alone.