Serenade No. 9 (Mozart)

9 in D major K. 320, Posthorn, was written by Wolfgang Amadeus Mozart in Salzburg, in 1779.

The manuscript is dated 3 August 1779 and was intended for the University of Salzburg's "Finalmusik" ceremony that year.

These were performed on their own in a concert in the old Vienna Burgtheater on 23 March 1783, along with the Haffner symphony, an aria from Idomeneo, and several other works.

[2] The first trio of the second minuet features a solo piccolo (called "flautino" in the manuscript) played over strings.

The second trio of the second minuet features a solo for the post horn.