Concealed from view, he is obliged to listen to an infantile scatological game played by the boy-man who is wildly attracted to the girl-woman. Salieri is scandalized by what he hears - and then astounded as music suddenly sounds from the great salon, and the boy springs up in alarm, cries “My music” and dashes from the room. This is Mozart? This giggling, naughty figure? And worse: the music Salieri hears—an adagio from the Wind Serenade for Thirteen Instruments—is the most beautiful he has ever heard in his life. God is apparently favouring not him, but a sniggering, unattractive little show-off.
From this moment, Salieri’s relations with his God begin to deteriorate. In the ensuing weeks he often meets Mozart, and the young man proceeds to unwittingly insult him in a variety of ways: firstly by sitting at the keyboard and turning the dull March of Welcome Salieri has composed into the brilliant tune later to be made world famous in “The Marriage of Figaro”-- Non Piu Andrai; secondly by seducing Salieri’s prize pupil Katerina Cavalieri, who sings the lead in the opera especially commissioned by a benevolent Emperor Joseph II. When his Majesty decides to show an additional mark of favour to Mozart by proposing him as a teacher of music to his royal niece, Salieri decides to block the appointment. Constanze, Wolfgang’s wife, appears secretly at Salieri’s house to plead for her husband, bearing with her manuscripts of his music as evidence of his ability. Salieri studies them as she waits. The manuscripts form an incredible miscellany of work—the slow movement of the Flute and Harp Concerto; the last movement of the Concerto for Two Pianos; the Twenty-ninth Symphony; the Kyrie from the C Minor Mass. Incredibly, these original and first drafts of the music show no corrections of any kind; it is just as if Mozart has taken down dictation from God Salieri reads on, overwhelmed, he is maddened by their perfection. Mozart has been chosen to be His instrument; Salieri must remain forever mediocre, despite his longings to serve. In fury he turns on the Deity. He makes demands of Him: “Why implant the desire to serve and then withhold the talent to do it? Why bestow your divine genius on Mozart, who is neither good nor chaste?” Goodness is nothing in the furnace of art. And for that reason he vows to ruin God’s incarnation—Mozart—as far as he is able.
Relentlessly Salieri plots to destroy Mozart. When “The Marriage of Figaro” comes to be produced, he does everything in his power—largely through the Italian faction at Court—to ruin it. Inevitably Mozart begins to sink into poverty and sickness.