The Palazzo Grimani in Venice Gennaro and his friends, including Orsini, celebrate on the brightly lit terrace, in front of which lies the Giudecca canal. The friends' conversation turns to Don Alfonso, Duke of Ferrara, to whose house they will be travelling the next day, and to his wife, the infamous Lucrezia Borgia. On hearing Lucrezia's name, Orsini tells of how Gennaro and he, alone in a forest, were warned by a mysterious old man to beware her and the entire Borgia family, and that the two of them would die together '. Professing his boredom with Orsini's tale Gennaro wanders off and falls asleep nearby. His friends are invited to rejoin the festivities, and he is left alone. A gondola appears and a masked woman steps onto the terrace. She hurries over to the sleeping Gennaro and observes him with affection. ' She kisses his hand, he wakes and is instantly struck by her beauty. He expresses his love for her and sings of his childhood as an orphan brought up by fishermen. He adds that he loves dearly the mother he has never met. The others return and instantly recognise her as Lucrezia Borgia, listing in turn the members of their families she has killed to Gennaro's horror.
Act 1
Ferrara The Duke, believing Gennaro to be Lucrezia's lover, plots his murder with his servant Rustighello ' Gennaro and his companions leave the house for a party and pass the Duke's palace with its large gilded coat of arms reading Borgia. Keen to show his contempt for the Borgia family, Gennaro removes the initial "B", leaving the obscene "Orgia". In the palace, Lucrezia is shown into the Duke's chamber. Having seen the defaced crest, she demands death for the perpetrator, not knowing that it is Gennaro. The Duke orders Gennaro to be brought before her and accuses him of staining the noble name of Borgia, a crime to which he readily confesses. Lucrezia, horrified, attempts to excuse the insult as a youthful prank, but Don Alfonso accuses Lucrezia of infidelity, having observed her meeting with Gennaro in Venice. In a scene full of drama and tension, she denies any impropriety, but he demands the prisoner's death and forces her to choose the manner of Gennaro's execution. Pretending to pardon him, the Duke offers Gennaro a glass of wine and he swallows it. After a stunning trio '' the Duke leaves and Lucrezia hurries to Gennaro, giving him an antidote to the poison the Duke has mixed with the wine. He drinks, and in a last duet, she implores him to flee the city and her husband. '
Act 2
The palace of the Princess Negroni Ignoring Lucrezia's advice, Gennaro attends a party at the palace, swearing never to be parted from his friend Orsini. Orsini leads the party in a brindisi or drinking song and they drink. Lucrezia enters and announces that in revenge for their insults in Venice she has poisoned their wine and arranged five coffins for their bodies. She has hitherto believed that Gennaro fled Ferrara on her advice, and is thus dismayed when he steps forward and announces that she has poisoned a sixth. Orsini, Liverotto, Vitellozzo, Petrucci and Gazella fall dead. Gennaro seizes a dagger and attempts to kill Lucrezia, but she stops him by revealing that he is in fact her son. Once again she asks him to drink the antidote, but this time he refuses, choosing to die with his friends. In a final cabaletta, Lucrezia mourns her son and expires.
Music
The closing cabaletta "Era desso il figlio mio" was added by Donizetti upon insistence by renowned soprano Henriette Méric-Lalande, who created the role of Lucrezia Borgia. It is one of the most demanding arias in all the operatic repertoire, with trills and coloratura passages that demand extreme vocal agility. Donizetti later removed the aria because he believed it damaged the credibility of the ending.
