The Importance of Stability in a Prince's Life

The great goal for princes is glory, not just power, but the power and the glory. If you're going to attain greatness, somehow you've got to be lucky says Machiavelli. The prince's aspiration to stability comes up against a great enemy: Fortuna. Chesley Borgia fell desperately ill at the moment when his enemies were coming for him. He could do nothing about this, but that means that he lost his state. So how do you become lucky in that sense?