- Lucrezia: "He killed my husband."
- Pietro: "Oh."
- Lucrezia: "Cesare has always been jealous of my attentions, but that should not deter us."
- —Lucrezia Borgia and her lover, Pietro Rossi, 1501.[src]
Before Alfonso married Lucrezia, her brother Cesare was impressed by his handsome looks and kind nature. However, once Lucrezia was happily married to Alfonso, she paid Cesare less romantic attention.
Wanting Lucrezia for himself, Cesare had his thugs attack Alfonso as a warning. In response, Alfonso sent his own men after Cesare. The latter then ordered Micheletto Corella to murder Alfonso. Micheletto entered the wounded Alfonso's bedchamber, where he strangled him to death. This caused Lucrezia great distress, and in retaliation, she rebelliously entered into affairs with men such as Patrizio and Pietro Rossi.