The Prince by Niccolo Machiavelli Chapter 3 Page 16

of necessity obliged to attach themselves to him, and with whose assistance, for they were many, he might readily have made himself safe against any other powerful State. But no sooner was he in Milan than he took a contrary course, in helping Pope Alexander to occupy Romagna; not perceiving that in seconding this enterprise he weakened himself by alienating friends and those who had thrown themselves into his arms, while he strengthened the Church by adding great temporal power to the spiritual power which of itself confers so mighty an authority. Making this first mistake, he was forced to follow it up, until at last, in order to curb the ambition of Pope Alexander, and prevent him becoming master of Tuscany, he was obliged to come himself into Italy.

And as though it were not enough for him to have aggrandized the