Wagenseil, Georg Christoph (b. Vienna, 29 Jan. 1715; d. Vienna, 1 Mar. 1777). A court composer in Vienna from 1739 until his death, organist at Empress Elizabeth Christine's private chapel (1741–50) and court keyboard instructor (from 1749), Wagenseil was a renowned composer of operatic, vocal, orchestral and chamber works. His prolific instrumental output alone totalled over 100 symphonies, 100 concertos and 200 works for solo keyboard. Wagenseil's prowess on the keyboard was widely praised, C. F. D. Schubart citing his ‘extraordinary expressive power’. Mozart learned a Wagenseil scherzo on 24 January 1761 (as reported by Leopold Mozart in Nannerl Mozart's music book), performed a Wagenseil concerto for Empress Maria Theresia on his first trip to Vienna in 1762, and played other keyboard works by him at court in London two years later. According to Friedrich Schlichtegroll's biography of Mozart in his Nekrolog auf das Jahr 1791 (Gotha, 1793), Wagenseil was present at the Vienna performance and may have turned pages for Mozart. On a later trip to Vienna, Leopold explained to his wife (30 Jan.–3 Feb. 1768): ‘I was told that all the clavier-players and composers in Vienna were opposed to our advancement, with the sole exception of Wagenseil, who, however, as he was ill at home, could not help us or contribute anything to our advantage.’

simon p. keefe