With a libretto by Felice Romani, Bellini’s frequent collaborator, the action takes place in Gaul during the Roman occupation, around 50 BC. Norma is a priestess sworn to chastity, but she has a secret relationship with Pollione, the leader of the enemy Roman forces, with whom she has two children. When he grows tired of her and falls for a young novice, Adalgisa, Norma erupts in fury. But in the end, with Pollione now her prisoner, she confesses before her people that she has broken her vows and deserves punishment: to die at the stake alongside Pollione, who is moved by the nobility and courage of this woman.

Norma is considered one of the peaks of the bel canto style—a genre cultivated by Bellini himself, as well as Donizetti and other composers of the time—which emphasized vocal expressiveness, with long, dramatic melodies, such as those found in the famous aria Casta diva, one of the most demanding pieces in the soprano repertoire.