Mozart, Largo.Molto allegro from Serenade No 10 for 13 Winds in B-flat major (Gran Partita K. 361).

The Serenade No. 10 for winds in B-flat major, K. 361/370a, is a serenade by Wolfgang Amadeus Mozart scored for thirteen instruments: twelve winds and string bass. The piece was probably composed in 1781 or 1782 and is often known by the subtitle Gran Partita, though the title is a misspelling and not in Mozart's hand. It consists of seven movements.
Some prominent authorities (Köchel, Tyson and Edge) suggest that the paper and watermarks of this work prove a composition date of 1781 or 1782. That the work was specially composed for a public concert given by Anton Stadler on March 23, 1784, is less likely, because this performance has no proven connection with the date of composition and only marks an ante quem date. The autograph of this work contains 24 leaves of paper-type 57. Four other compositions that used this paper can be securely dated to 1781. It was shown by Alan Tyson that this fact is sufficiently compelling to presume that K. 361 was composed in 1781. There is no evidence whatsoever that the 24 leaves of this paper-type that appear in the autograph of K. 361 were ever intended for anything other than K. 361, and it is clear from the pattern of paper-usage that K. 361 was the principal project for which Mozart acquired that paper-type.
The documentary history also shows that there is an unequivocal reference to wind-band music in Vienna in 1781. The performance of only four movements in 1784 generated the belief that the work was composed in two stages, though this view is now rejected.