- Andrea Orsini: [looking at the dead body of Lucrezia Borgia's husband] Would you say the dead man made a reluctant corpse?
- Don Esteban: A loose tongue soon loses its mouth, Captain Orsini.
- Andrea Orsini: A wise tongue never needs to repeat itself, Don Esteban, nor does a competent assassin.
- Don Esteban: [after getting a shove from behind from Borgia] My Lord!
- Cesare Borgia: My garden is filled with beautiful women and you stand here like a brooding nemisis!
- Don Esteban: I was thinking.
- Cesare Borgia: Good. Practice makes perfect.
- [Walking away]
- Cesare Borgia: You should listen though. You may learn something.
- Cesare Borgia: [Describing a man who would fit his requirements as an agent] ... be as quick at deceit as a fox. He must have the grace of a dancer; the wrist of an assassin. He must have little regard for good faith, yet by his astuteness, be able to confuse men's minds. He must have confidence in himself, yet not let that confidence render him incautious. He must charm as a snake charms a bird, yet he must make no friends, except those who can be of use to him and, for the same reason, although he may make use of love, he must not love."
- Cesare Borgia: [to Orsini] But the great know only one law: the outcome justifies the act. Have you the stomach for greatness?
- Andrea Orsini: The stomach and the appetite.
- Mona Constanza Zoppo: [responding to a noise outside her cottage which has disturbed her dog] Mice, rabbits, cats - a widow's dog never rests.
- Andrea Orsini: I believe that I was born and that I must die, and that I must make the best of what lies between the two extremes.
- Andrea Orsini: Heroism is a shallow thing, Madonna, if it isn't rooted in wisdom.
- Camilla Verano: I don't intend to be wise; I can only be what I am.
- Andrea Orsini: I asked to be taken to Duke Cesare Borgia.
- Don Esteban: By his orders I sit in his seat.
- Andrea Orsini: Well, sit lightly, my friend, lest you damage your brains.
- Count Marc Antonio Verano: [to Andrea] I've lived seventy years, and know in spite of the poets, youth is not the happiest season.