"Simon Boccanegra" was first performed at Teatro La Fenice, Venice on 12 March 1857. It was not very successful, and many years later Verdi made a lot of changes to it. He was helped by the writer Arrigo Boito who made changes to the plot. The new version was first performed at La Scala, Milan on 24 March 1881. This is the version that is normally performed today.