The opera was first given at La Scala in Milan on December 26,1819, where it ran for 39 performances and subsequently travelled to the major Italian cities, Vienna, Lisbon and Barcelona. As usual, It suffered the fate of many of Rossini's operas, ie. it was frequently cut, altered, or other music inserted into it. The Pesaro revival of 1986 was based on a critical edition of the original1819 score.

ACT I

The scene is St. Mark's Square in Venice, the eighteenth century.

A chorus celebrates the victory of the Venetian forces over a foreign conspiracy. Contareno and Capellio, Venetian senators, meet with the hope of ending an ancient feud that has divided their families. Capelio asks for the hand of Bianca, Contareno's daughter. This union would also serve to restore the waning fortunes of Contareno's family and he accepts the proposal. Cannon shots announce the arrival of the Doge who enters with his court. He decrees the restoration of the death penalty for any Venetian noble in secret contact with a foreign ambassador. Capellio objects to the severity of the law since the conspiracy has been defeated. The Doge states that the danger of new attacks is still present, especially with the death of their courageous general Falliero. However, a messenger appears to announce that Falliero is returning victorious. Falliero enters with his officers and accepts the praise and gratitude of the people. The scene changes to a hall in Contareno's house. Bianca and her handmaidens express their joy at the safe return of Bianca's beloved, Falliero. Costanza, her nurse, describes the festivities planned to celebrate his victorious campaign and tells Bianca of Falliero's intention to ask Contareno for her hand. All, save Bianca, leave as Contareno enters. He reminds Bianca that her marriage to an affluent house is necessary to restore their family's fortune. To Bianca's surprise, he announces his arrangement for her to marry Cappella. He is furious when she expresses her preference for Falliero. He demands her complete obedience and threatens to disown her and ruin Falliero if necessary. Overcome, Bianca agrees to his demands. The scene changes to a room in Contareno's house.

Falliero tells Costanza of his plans to ask Contareno for Bianca's hand. Costanza confirms Bianca's faithfulness. She leaves and Bianca enters. Disconsolate, she tells Falliero of her father's disapproval of him, through not of Contareno's threats. Though Falliero beseeches her, Bianca will not defy her father. As they part, Falliero is left to question her sincerity. The wedding entourage enters followed by Contareno, Capellio, and Bianca. She is resigned to accept her father's demands and marry Capellio yet she hesitates to sign to marriage certificate. Falliero burst in and accuses Bianca of being unfaithful. They both express their conflicting emotions to which are added those of Contareno and Capellio. The assembly erupts into various oaths and threats as the act ends.

ACT II

The scene is a garden in Contareno's house, which adjoins the Spanish Embassy. Costanza has convinced Bianca to meet with Falliero one last time. He enters and they reaffirm their love but Bianca insists that she cannot disobey her father. Costanza enters to warm of Contareno's approach. With no other exit available, Falliero escapes over the wall into the Spanish Embassy. Contareno enters insisting that the marriage ceremony resume immediately. Bianca continues to refuse to sign the contract. As Capellio is about to break off the marriage, Pisani enters with the news that Falliero has been caught on the grounds of the Spanish Embassy. According to the Doge's decree, the Triumvirate Council must meet to decide his fate. Contareno sees an opportunity to finally rid himself of the troublesome hero as Bianca begs him to save her beloved. The scene changes to the assembly hall of the Triumvirate Council.

Soldiers and porters prepare the hall for Falliero's trial, expressing their shock that their hero has turned traitor. Falliero is led in. As he muses on his predicament, he reflects on his love for Bianca. He asks the names of the Council members; they are Loredano, Capellio and Contareno. He believes himself lost but Pisano tells him that Capellio is merciful and the vote must be unanimous or the decision passes to the Senate. He also tells Falliero, incorrectly, that Bianca and Capellio have wed. Falliero is stunned and dispirted and would prefer death to this news. Before the Council, Falliero will not defend himself. He is ready to sign a confession when Bianca enters. Contareno orders her to leave but Capellio demands to hear her. The four principals express their varying reactions to the impending outcome. Bianca relates the entire incident and declares her love for Falliero. Contareno moves to have Falliero condemned but Capellio denies his consent, forcing the vote to be sent to the Senate. The scene changes to a room in Catareno's house. Bianca enters, anxious over the fate of Falliero. Capellio enters with the Venetian nobles, followed by Falliero who rushes into Bianca's arms. He has been absolved. Bianca expresses her happiness. When Contareno finally capitulates and agrees to the union of Falliero and his daughter, all join Bianca in her outpouring of joy as the opera ends.