Puccini's first full-length opera, Edgar, is set in Flanders in the year 1302, the scene of the Battle of Courtray, unlike the play upon which it was based. That earlier work, Alfred De Musset's La coupe et les lèvres [The cup and the lips] (1832), is set in the Tyrol, and its title refers to the saying “there's many a slip ‘twixt the cup and the lip.” Indeed, many a “slip” occurred in the creation of this opera, which was a disheartening debacle.

Edgar actually arose from several failures: Musset's play was written following the disaster of his La nuit vénitienne (1830), after which he withdrew from presenting plays in public and wrote dramatic works intended to be read at home. La coupe was one of several plays collected in his ensuing Armchair Theater [Un spectacle dans un fauteuil], and is prefaced by a long poem that, in part, reflects the pain of his artistic spurning:

Ferdinando Fontana chose Musset's La Coupe for his new libretto, and perhaps was also inspired by the Frenchman to write his own diatribe against contemporary theater, In Teatro. Fontana called it his “tirade” [sfuriata] and in it described his antipathy toward contemporary theater, inveighing against its predictability and lack of naturalism: