The Serenade for Orchestra no. 9, K. 320, nicknamed Posthorn, was written by Wolfgang Amadeus Mozart in 1779, intended for the university "finalmusik" ceremony that year. The serenade is scored for 2 flutes, 2 oboes, 2 bassoons, 2 horns, 2 trumpets, post horn, timpani and strings. The Concertante and Rondeau movements feature prominent concertante sections for flute and oboe. A typical performance lasts approximately 45 minutes.
