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
Haydn and Mozart symphony and a chorus, both probably from [the oratorio] "Il ritorno di Tobia"") and Mozart ("a new concert aria, probably 'Misero! o sogno!' [K. 431], and, on the first night, a piano concerto") At the time of this meeting, Haydn was the most celebrated composer in Europe. Mozart's own reputation was definitely on the rise. His opera "The Abduction from the Seraglio" had been premiered with great success in Vienna, and was being produced in several other cities. Haydn would have been about 52 at the time, Mozart about 28. Jens Peter Larsen suggests that "quartet playing was central to