From Machiavelli’s Discourses, I.27:
When Pope Julius II went to Bologna in 1505 to expel from that state the house of Bentivogli, which had held the princiapte of the city for a hundred years, he also wished – as one who had taken an oath against all the tyrants who seized towns of the church – to remove Giovampagolo Baglioni, tyrant of Perugia. Having arrived near Perugia, with this intent and decision known to everyone, he did not wait to enter that city with his army, which was guarding him, but entered it unarmed, notwithstanding that Giovampagolo was inside with many troops that he had gathered for defense of himself. So, carried along by that fury with which he governed all things, he put hiimself with a single guard in the hands of his enemey, whom he then led away with him, leaving a governor in the city who would render justice for the church. The rashness of the pope and the cowardice of Giovampagolo were noted by the prudent men who were with the pope, and they were unable to guess whence it came that he did not to his perpetual fame, crush his enemy at a stroke and enrich himself with booty, since with the pope were all the cardinals with all their delights. Nor could one believe that he had abstained either through goodness or through conscience that held him back; for into the breast of a villainous man, who was taking his sister for himself, who had killed his cousins and nephews so as to reign, no pious respect could descend. But it was concluded that it arose from men’s not knowing how to be honorably wicked or perfectly good; and when malice has greatness in itself or is generous in some part, they do not know how to enter into it.
So Giovampagolo, who did not mind being incestuous and a public parricide, did not know how – or, to say it better, did not dare, when he had just the opportunity for it – to engage in an enterprise in which everyone would have admired his spirit and that would have left an eternal memory of himself as being the first who had demonstrated to the prelates how little is to be esteemed whoever lives and reigns as they do; and he would have done a thing whose greatness would have surpassed all infamy, every danger, that could have proceeded from it.
From the translation by Harvey C. Mansfield and Nathan Tarcov.