Mozart's penultimate symphony is so well known, even by people who rarely attend orchestral concerts, that little introduction is necessary, except to answer the question, "With or without clarinets?" Around the time when he wrote this work, many of Mozart's most sublime creations featured the instrument, yet Mozart rarely included the clarinet in the orchestration of his symphonies. Indeed, the original manuscript of K. 550 (which Mozart may never have heard performed) featured only flute, oboes, bassoons and horns in its wind section. Anton Stadler, the musician whose artistry inspired Mozart to write his clarinet concerto and clarinet quintet, played in the orchestra at the first documented performances of the work in April 1791, and it may be due to him that Mozart revised the orchestration, sketching new parts for oboes and clarinets but leaving the remaining wind and string parts untouched.