Mozart was traveling with his father in Italy when he wrote this tiny symphony, and not surprisingly the work is in the style of an Italian overture of the time, and does without the noisy support of trumpets and drums. Mozart began it in Milan during carnival time and finished it a few months later in Bologna. It's possible that he intended it as the overture to his opera Mitridate, re di Ponto. At any rate, it follows the Italian three-movement form. The first movement, overture style, is marked merely Introduction and opens with slashing, attention-getting chords, as if to signal the imminent beginning of a drama. The principal motif is a routine walk up and down the scale, complicated by some formulaic Lombardic ideas, but Mozart comes into his own here with the syncopated figures in the second main subject. The development section is really just a miniscule transition to the recapitulation.
Without pause, this leads to the pastoral Andante, full of trilling birdsongs and music suggesting burbling brooks, while essentially taking the form of a minuet. The last movement, Allegro, is a brief rondo, launched by a scurrying violin figure and soon toying with syncopation and pizzicati.