Vestas Feuer by Pamina and Papageno in "The Magic Flute"), which has the same key and time signature and was the subject of a set of variations for cello and piano by Beethoven (WoO 46), written 1801. Lockwood also discerns a precedent set by Mozart involving formal structure: an "Introduzione"; i.e. Beethoven's scene forms a separable initial section of an opera having some degree of integrity of both plot and harmonic plan; Lockwood calls the "Introduzione" a "miniplay". Three of Mozart's operas begin with such an "Introduzione": "Don Giovanni", "Così fan tutte", and "The Magic Flute". Beethoven's "Introduzione" has a harmonic structure
Mozart and Salieri (opera) on his "Requiem", which a stranger in black commissioned from him. Mozart recalls Salieri's collaboration with Pierre Beaumarchais and asks if it could be true that Beaumarchais once poisoned someone, for genius and criminality are surely incompatible. Salieri then surreptitiously pours poison into Mozart's drink. Mozart begins to play at the keyboard, as Salieri begins to cry. Mozart sees this, but Salieri urges Mozart to continue. Mozart begins to feel ill, and leaves. Salieri ends the opera pondering Mozart's belief that a genius could not murder: did not Michelangelo kill for his commissions at the Vatican, or were those idle