• Giuseppe Verdi. Opera in a prologue and three acts. 1856.
• Libretto by Francesco Maria Piave, with contributions from Giuseppe Montanelli, after the play Simón Bocanegra by Antonio García Gutiérrez. Revised by Arrigo Boito for La Scala, Milan in 1881.
• First performance at the Teatro La Fenice, Venice, on 12^th March 1857.

In the prologue Paolo and Pietro agree to put forward the name of the plebeian Boccanegra for election as Doge of Genoa. Boccanegra agrees, thinking to facilitate his marriage to Maria, daughter of the reigning Doge, Fiesco. Maria dies but bears him a daughter, who subsequently disappears. 25 years later Amelia is in the garden of the Grimaldi palace, serenaded by her lover Gabriele Adorno, and confiding in him her fears for his safety and that of her guardian Andrea, Fiesco in disguise, both conspirators against the Doge. Fiesco tells Adorno that Amelia is not a true Grimaldi but an orphan, but blesses their intended union. Boccanegra had intended that Amelia marry his courtier Paolo but when he realises that she must be his long-lost daughter he changes his mind. Paolo secretly plans to abduct her. In the second scene Boccanegra is accused of her abduction, but is exonerated by Amelia, who does not reveal the name of the perpetrator. Boccanegra insists that the guilty man be cursed, a curse in which Paolo is compelled to join, to his horror. In the second act Paolo plans to poison Boccanegra, but Fiesco will not join the plot. Gabriele accuses Amelia of infidelity. He determines to murder the Doge, now sleeping after drinking from the cup Paolo has poisoned. He is prevented by Amelia, who reveals herself as Boccanegra's daughter, leading to the reconciliation of the three. Sounds of popular rebellion are heard, and Gabriele promises to support the Doge. In the third act, the rebellion now quelled, Paolo admits his crimes and is led away to execution. The poison works gradually on Boccanegra, who is now reconciled with Fiesco, his own identity revealed and that of Amelia, his grand-daughter. As he dies, Boccanegra blesses Gabriele and Amelia, and appoints the former as Doge.

It is generally thought that the 1881 revision of Simon Boccanegra improved the work by adding some light to the general gloom and giving further prominence to Boccanegra himself. It is the revised version that is usually performed. The prologue provides Fiesco with his moving Il lacerato spirito (The tortured spirit). In the first act dawn breaks in the Grimaldi palace garden, leading to Amelia's In quest'ora bruna (In this dark hour), while the more spectacular second scene, in the Council Chamber, brings Boccanegra's effective Plebe! Patrizi! (Plebeians! Nobles!) that quells incipient disturbance. Gabriele Adorno has his own particular moment of jealous anger in Sento avvampar nell'anima (I feel burning in my soul).