Persuasion and Fortune

I have always believed that when a man takes it into his head to accomplish some project and pursues it to the exclusion of everything else, he must succeed in it despite all difficulties; such a man will become the Grand Vizier, he will become Pope, he will overthrow a monarchy, provided that he begins early; for the man who has reached the age which Fortune disdains no longer succeeds in any undertaking, and without her help one can hope for nothing. The thing is to count on her and at the same time to defy her reverses. By this is one of the most difficult of political calculations.

Giacomo Casanova - History of my life (4, 13)