- Cesare Borgia: [after his fortress is infiltrated by one of his enemies] Do you see what danger we face? Hiding behind walls will not win campaigns. We must attack! I need weapons, engines of death. You are my engineer. Create me weapons that will destroy my enemies.
- Leonardo: This is not why I came here.
- Cesare Borgia: You've re-routed rivers from their course. You've designed cities, all in my name. What man was ever given this chance? I've made you into a god, Leonardo. You cannot forsake me.
- Leonardo: I wish to go home.
- Cesare Borgia: You and I, we are the same. We don't need the things that others need. We don't need to be loved. Not when we can inspire awe and fear. A hundred miles along the Roman road. Give me a hundred corpses.
- Leonardo: What?
- Cesare Borgia: You truly wish to go home? Design a weapon that will slaughter a hundred souls. That is the only way that you will buy your own soul back.
- Lisa Del Giocondo: Is there a problem, Maestro?
- Leonardo: I'm sorry, Madonna. I'm... I'm not sure I know how to paint you.
- Lisa Del Giocondo: I don't understand.
- Leonardo: If I'm to paint you, I must see more than your outward appearance. I must see who you really are. The soul inside.
- Lisa Del Giocondo: Surely, that is not so difficult.
- Leonardo: God takes your child, and yet you smile.
- Lisa Del Giocondo: I am grateful for the time I had with her. I am so grateful for the memories. Suffering brings you closer to God.
- Leonardo: I've sought only to get closer to God's truth through beauty.
- Lisa Del Giocondo: If it is truth you are seeking, then perhaps you are looking in the wrong place. There is only one truth we as mortals can ever hope to know. And that is love.
- Leonardo: Forgive me, Madonna, but you are in mourning.
- Lisa Del Giocondo: Yes, my daughter Lucrezia. She left us when she was only six months old.
- Leonardo: I'm so sorry.
- Lisa Del Giocondo: I miss her every day. She was so sweet-natured, so full of life.
- Leonardo: Your eyes shine when you speak of her.
- Leonardo: Ambition can destroy a man's soul.
- Stefano Giraldi: Are you talking about me?
- Leonardo: I heard the guards talking. They said your promotion depends on getting my confession.
- Stefano Giraldi: I'm not going to put you on the rack. If that's what you're worried about.
- Leonardo: Why not?
- Stefano Giraldi: Torturing gets people to tell us what we want to hear. I want the truth.
- Leonardo: Even at the cost of your own self-interest?