Franz Xaver Gerl have been the composer of the aria "Ein Weib ist das herrlichste Ding", for which Mozart wrote a set of variations for piano, K. 613 (the composer may instead have been another singer-composer in the troupe, Benedikt Schack). Mozart gradually came to participate more in the activities of the Schikaneder troupe, culminating in his opera "The Magic Flute" (1791), with libretto by Schikaneder. Gerl premiered the role of Sarastro, and continued to sing this part in many performances through 1792. He left Schikaneder's troupe in 1793. Gerl may have been a participant in a rehearsal of Mozart's "Requiem" on the
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