Opera in prol. and 3 acts by Verdi to lib. by Piave and Montanelli, based on play Simón Boccanegra by Gutiérrez. Comp. 1856–7. Prod. Venice 1857. Lib. rev. by Boito 1880, Verdi revising the score and composing new council chamber scene (Act I, Sc. 2). Prod. Milan 1881, NY Met 1932, London (SW) 1948.