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 smallpox both children's illness to contend with, the Mozarts spent a total of four months away from Vienna. They eventually returned there and were received in the Imperial court on 19 January, 1768. The Empress, who had by now lost three children to smallpox, conversed with Frau Mozart about the disease. The remainder of the trip was not especially successful. Leopold apparently misinterpreted a chance remark of the Emperor as a firm invitation for Wolfgang to compose an opera; this resulted in Wolfgang writing "La finta semplice". However, the opera went unperformed in Vienna; the singers and musicians did not like