La sonnambula (The Sleepwalker) is an opera semiseria in two acts, with music in the bel canto tradition by Vincenzo Bellini set to an Italian libretto by Felice Romani, based on a scenario for a ballet-pantomime written by Eugène Scribe and choreographed by Jean-Pierre Aumer called La somnambule, ou L'arrivée d'un nouveau seigneur. The ballet had premiered in Paris in September 1827 at the height of a fashion for stage works incorporating somnambulism.
The role of Amina was originally written for the soprano sfogato Giuditta Pasta and the tenor Giovanni Battista Rubini, but during Bellini's lifetime another soprano sfogato, Maria Malibran, was a notable exponent of the role. The first performance took place at the Teatro Carcano in Milan on 6 March 1831.
The majority of twentieth-century recordings have been made with a soprano cast as Amina, usually with added top-notes and other changes according to tradition, although it was released in soprano sfogato voice (not be confused with the modern mezzo, nonexistent at the time) who sang soprano and contralto roles unmodified.
The phrase Ah! non credea mirarti / Sì presto estinto, o fiore ("I did not believe you would fade so soon, oh flower") from Amina's final aria is inscribed on Bellini's tomb in the Catania Cathedral in Sicily.