Berlioz wrote his Roman Carnival Overture in 1844, recycling two extracts from his opera Benvenuto Cellini – the love duet from the first act (Andante) and the carnival scene (Allegro vivace).
The dramaturgy of the opera also justifies Berlioz’s choice. Teresa, the child of the Cardinal’s treasurer, loves Cellini the goldsmith, but her father intends her to marry the sculptor Fieramocsa. Cellini sneaks into Teresa’s room in the night. Their love duet begins in the sweet melodic style of Italian songs, but the man’s avowal gradually takes the scene into increasingly passionate territory. They plan that Teresa will be spirited away during carnival time (and this being an opera, Fieramosca is naturally on hand to eavesdrop.)

The description of the carnival is a large scale dramatic tableau and one of Berlioz’s greatest theatrical scenes. The colourful commotion, the elemental music, the precisely evoked mood, sound and colours of southern folk festival is irresistible. The Hungarian musicologist György Kroó characterised its historic importance, calling it the progenitor of the closing  crowd scene of Act 2 of Wagners’s Meistersingers, and the Krom tableau from Mussorgsky’s Boris Gondunov. Berlioz constructs the sweeping Allegro of the overture from three themes sung by the thronging  masked crowd (the chorus): “Venez, venez peuple de Rome” (Come, come, people of Rome), “Mais déjŕ la foule, Dans l’ombre et la nuit” (“But the crowd is in the shadow and the night”) and “Ah sonnez trompettes” (“Let the trumpets sound.”)