The Prince by Niccolo Machiavelli Chapter 20 Page 7

confidence; and Pandolfo Petrucci, Lord of Siena, governed his State by the instrumentality of those whom he had at one time distrusted, in preference to all others. But on this point it is impossible to lay down any general rule, since the course to be followed varies with the circumstances. This only I will say, that those men who at the beginning of a reign have been hostile, if of a sort requiring support to maintain them, may always be won over by the Prince with much ease, and are the more bound to serve him faithfully because they know that they have to efface by their conduct the unfavourable impression he had formed of them; and in this way a Prince always obtains better help from them, than from those who serving him in too complete security neglect his affairs.

And since the subject suggests it, I must not fail