PROLOGUE. In a piazza in fourteenth-century Genoa, Paolo and Pietro, leaders of the popular (plebeian) party, conspire to gain power over the aristocracy (patricians). They name the popular former pirate Simon Boccanegra as their candidate for the office of Doge, the chief magistrate of the republic. Boccanegra accepts, hoping that his position will enable him to marry Maria, who has been imprisoned by her father, the patrician Fiesco, because she bore Boccanegra an illegitimate child. The plebeians pledge their support to Boccanegra. When they leave, Fiesco appears, mourning Maria’s death. Boccanegra, unaware she has died, returns and tries to make peace with the patrician. Fiesco demands that he first be given his grandchild, but Boccanegra explains that she has disappeared (“Del mar sul lido”). Fiesco leaves and Boccanegra enters the palace, discovering Maria’s body. As he staggers outside, the crowd proclaims him Doge.
[Twenty-five years elapse between the Prologue and Act I. During this time, Boccanegra has exiled many of his political opponents and confiscated their property. Fiesco, now exiled, lives outside Genoa in the Grimaldi Palace under the assumed name of “Andrea.” He is the guardian of a certain Amelia Grimaldi. The infant daughter of Count Grimaldi had died in a convent near Pisa. The same day she died, an orphan was discovered on the convent grounds and brought up in the dead girl’s place. She was given the name Amelia Grimaldi in order to provide the family with an heiress and to protect their property from confiscation when they became political exiles. Amelia is in reality Maria Boccanegra, the daughter of Simon Boccanegra and Maria, Fiesco’s dead daughter. Neither Fiesco nor Boccanegra know Amelia’s true identity. Amelia’s lover is the patrician Gabriele Adorno. Gabriele and Fiesco, whom he knows only as “Andrea,” have been plotting against the Doge Boccanegra.]
ACT I. Scene 1. Amelia waits for her lover Gabriele in the seaside garden of the Grimaldi Palace (“Come in quest’ora bruna”). He arrives, and she warns him against the dangers of plotting against the Doge, and turns his thoughts to love. Gabriele learns from Amelia that the Doge wants her to marry his courtier Paolo. Gabriele resolves to obtain the blessing of her guardian, Andrea. The young man is not dissuaded by Andrea’s revelation that Amelia is not a true Grimaldi but an orphan of unknown background. Determined to overthrow the Doge, the men leave just as a fanfare announces Boccanegra, who tells Amelia he has pardoned her foster brothers. Impressed by his generosity, she admits her love for Gabriele and describes her lonely past. Boccanegra, hearing the story, produces a locket with a likeness of the dead Maria and finds that Amelia has an identical locket. Boccanegra realizes that Amelia is his long-lost daughter Maria, and they embrace (“Figlia! a tal nome io palpito”). When the Doge tells Paolo to forget his dream of marrying Amelia, Paolo plots with Pietro to kidnap her.
Scene 2. In the Council Chamber of the Doge’s Palace, during a debate about a peace treaty with Venice, angry shouts are heard from the street. Gabriele, chased indoors by the mob, has killed a man who was attempting to abduct Amelia. He accuses Boccanegra of plotting the abduction. As Gabriele tries to stab the Doge, Amelia intervenes, pleading for the life of Gabriele, who suspects her of being Boccanegra’s mistress. Amelia describes her abduction to the Council, hinting at Paolo’s complicity, and Boccanegra urges peace for the warring factions (“Plebe! Patrizi!”). He commands Paolo to curse the man behind the kidnapping, and the terrified Paolo is forced to obey, even though he is cursing himself.
ACT II. In the Doge’s chambers at night, Paolo sends Pietro to free Gabriele and Andrea from prison. Remembering the curse, he pours poison into Boccanegra’s water pitcher (“Me stesso, ho maledetto!”). When the two prisoners enter, Paolo tries to convince the old man to assassinate the Doge, inciting Gabriele with insinuations about the Doge’s relationship with Amelia. Gabriele raves with jealousy (“Sento avvampar nell’anima”) until Amelia enters; before she can explain, Boccanegra is heard approaching. Gabriele hides while Amelia asks the Doge to pardon her lover; otherwise, she will die on the scaffold with him. Boccanegra agrees on the condition that Gabriele leave the conspirators. Left alone, the weary ruler drinks the poisoned water. He falls asleep. Gabriele, who has heard nothing of the preceding conversation, enters and is about to stab Boccanegra when Amelia rushes in and stops him. The Doge awakens and at last reveals to Gabriele that he is Amelia’s father. He forgives the repentant Gabriele while Amelia prays to her mother in heaven. A rebellious mob gathers outside, and Gabriele says he will pacify them or die in Boccanegra’s defense. The Doge offers him Amelia’s hand in marriage as his reward.
ACT III. Genoa is celebrating Boccanegra’s victory over the rebels. Andrea, set free, encounters Paolo on his way to execution. Paolo admits that he poisoned the Doge. A herald announces that the celebrations must cease in honor of the fallen heroes. Boccanegra staggers in, mortally ill. Andrea reveals his identity as Fiesco, and learns from the Doge that Amelia is his granddaughter. The old man weeps at learning the truth too late and tells Boccanegra of the vengeful Paolo’s poison. Dying, the Doge blesses the young couple, naming Gabriele his successor (“Gran Dio, li benedici”). Fiesco sadly announces Boccanegra’s death to the people.