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
Piano concertos by Wolfgang Amadeus Mozart In the works of his mature series, Mozart created a unique conception of the piano concerto that attempted to solve the ongoing problem of how thematic material is dealt with by the orchestra and piano. With the exception of the two exceptionally fine early concertos K. 271 ("Jeunehomme") and K. 414 (the "little A major"), all of his best examples are from later works. Mozart strives to maintain an ideal balance between a symphony with occasional piano solos and a virtuoso piano fantasia with orchestral accompaniment, twin traps that later composers were not always able to avoid. His resulting solutions