Opera in four acts; libretto by Tobia Gorrio (Arrigo Boito),
based on the play "Angelo, tyran de Padoue" by Victor Hugo.

First performance: Milan, La Scala, 8th April 1856

Characters:
La Gioconda, singer (soprano)
Laura Adorno, Genoese, wife of Alvise (mezzo-soprano)
Alvise Badoero, one of the leaders of the Inquisition (bass)
La cieca, Gioconda's blind mother (contralto)
Enzo Grimaldo, Genoese nobleman (tenor)
Barnaba, minstrel (baritone)
Zuàne, competitor in the regatta (bass)
A cantor (bass)
Isèpo, public scribe (tenor)
A pilot (bass)

ACT ONE

The people are celebrating the generosity of the Republic. The minstrel Barnaba, who in reality is a spy working for the Council of Ten, reflects on the ambiguity of the Venetians. The Republic keeps a tight hold on its power with a mixture of festivals and executions. Gioconda arrives with her blind mother. As she awaits the celebration of vespers, the girl leaves her mother to join her beloved Enzo. On her way, however, she runs into Barnaba, who makes advances to her. The girl rejects him scornfully and runs off. In the meantime the people come back onto the scene bearing the winner of the regatta in triumph. Barnaba convinces them that he lost the regatta because of a curse pronounced by the old blind woman who is praying. The crowd want to lynch her. Gioconda and Enzo arrive; Enzo tries to defend the old woman but realising that he can do nothing, he runs to seek help. Alvise Badoero, who has appeared with his wife Laura, succeeds in restoring calm to the piazza. Gioconda tries to defend her mother, but only Laura believes her. Enzo comes back with a group of sailors. Laura, who is masked and cannot be recognised, is struck when she sees his face. She sees a rosary in the hands of the old blind woman and pronounces an absolution. Barnaba takes Alvise aside and tells him that he will soon capture one of the Republic's enemies. Gioconda asks the name of the woman who has saved her mother. Laura speaks her name and Enzo is clearly agitated. When all the others move towards the church, he stays alone. Barnaba steps up to him and tells Grimaldo that he has discovered his real identity. Enzo is not the Dalmatian sailor he pretends to be but a Genoese prince banished from the Republic who has now come back to Venice in disguise to find an old love, a girl who has been promised to another man. Barnaba insists: Enzo does not love Gioconda at all, his heart beats for the woman who has just saved Gioconda's old mother, Laura. The minstrel offers to help Enzo, telling him that he can meet Laura that very night on the ship. Alvise will be away and will suspect nothing. Enzo is delighted and agrees, but then asks who Barnaba really is. The chilling answer is that he is the powerful demon of the Council of Ten, the man who could have him arrested if he wished. Barnaba loves Gioconda and wants to be avenged for the fact that she does not love him. Killing the man she loves is not enough, however; he would rather drive Enzo to betray her with Laura. Enzo is shaken by what he has heard, but agrees to meet Laura. Barnaba immediately informs Alvise of Enzo and Laura's treachery. Gioconda, who has overheard everything, rushes into the church and comes out supported by her blind mother.

ACT TWO

A group of sailors are singing a merry song on Enzo's ship. Barnaba is disguised as a fisherman: in reality he is weighing up the defences of the brigantine. Barnaba leaves. Enzo orders his men to leave then sends them below. Laura arrives accompanied by Barnaba and is left alone with her lover. The two embrace, then Enzo goes below to prepare their escape. Suddenly Gioconda appears, wearing a mask. She is holding a dagger and wants to kill Laura, but then sees Alvise approaching and decides to hand the faithless woman over to her husband. To defend herself Laura lifts up the rosary given to her by Gioconda's old mother; now Gioconda realises that this is the lady who saved her mother's life. Before Alvise sets foot on the brigantine Gioconda masks her rival and entrusts her to two sailors. Then, angry and sarcastic, she tackles Enzo on the bridge. Two Venetian galleys attack and sink the brigantine.

ACT THREE

Alvise has decided to punish his wife's betrayal with death. Laura enters and a heated exchange ensues. Then Alvise hands her a phial of poison, ordering her to kill herself. Gioconda manages to substitute a powerful sleeping draught for the poison and has Laura drink it. Alvise receives his guests at the Ca' d'Oro. Then Enzo arrives, accompanied by Gioconda's mother. Enzo faces up to Alvise asking him where Laura is. Alvise tells him that he has executed her and shows him her unmoving body.

ACT FOUR

In the entrance of a house on the Giudecca, Gioconda says goodbye to a group of trusted friends who have hidden Laura's body, and asks them to seek her mother, who has been missing since the previous evening. Alone now, Gioconda falls into despair. She considers taking her own life but then reflects on the fact that she must help Laura to get away. She calls Enzo. Enzo arrives. He too is desperate; he thinks Laura is dead. Gioconda tries to rekindle the love he once had for her, but it is useless. Offended now, she tells Enzo that she has stolen Laura's corpse. Enzo asks her to explain, but Gioconda is no longer listening to him. All she wants to do now is to die. Enzo is about to attack Gioconda when the effect of the sleeping draught wears off and Laura wakes up and tells Enzo everything that has happened.
Enzo throws himself at Gioconda's feet with his beloved Laura, then the two run off. Gioconda is all alone now and is held back from suicide only when she thinks of her mother and the pact she has made with Barnaba. Barnaba arrives bringing the girl's blind mother. In exchange for her mother he wants a night of passion: the girl pretends to agree but at the last moment she stabs herself with a dagger.