Boito was twenty-six when Mefistofele reached La Scala on 5 March 1868, in a version lasting more than five hours which he conducted himself. The reception was hostile enough that the police intervened, and the opera was withdrawn after two performances. Boito spent seven years cutting and rewriting — an entire act went, and the title role moved from baritone to bass — and the revised version, given at Bologna on 4 October 1875, succeeded. Unlike Gounod he took in both parts of Goethe, from the prologue in heaven to Helen of Troy, keeping the philosophical frame rather than the love story alone.