The circumstances and achievements of Beethoven's youth are not the stuff of legend as Mozart's are, in part because Beethoven's father Johann had neither the musical talent nor the entrepreneurial ambition of Leopold Mozart. Yet Beethoven's father was a professional musician who started his son early in the family business (Beethoven's grandfather, also Ludwig, was the distinguished Kapellmeister of the Electoral court at Bonn) and the young Ludwig gave his first advertised public performance at the age of seven. By age 11 he was serving as deputy organist to his teacher, Christian Gottlob Neefe, and had his first published composition issued, as the following notice from the Magazin der Musik indicates:

"Louis van Beethoven, son of the tenor singer already mentioned, a boy of 11 years and of the most promising talent. He plays the piano very skillfully and with power, reads at sight very well, and I need say no more than that the chief piece he plays is The Well-Tempered Clavier of Sebastian Bach, which Herr Neefe put into his hands… [Neefe] is now training him in composition, and for his encouragement has had nine variations for piano, written by him on a march, engraved at Mannheim."

Bonn was noted for its wind bands during this period, and Beethoven wrote a fair bit of chamber music that included wind instruments then. Some of it was published much later in his life, with misleadingly high opus numbers, and some of it was published without opus numbers or not at all during Beethoven's life, such as this Trio that he composed probably in 1786, when he was 15 years old. (WoO is the German abbreviation for "work without opus.") One of the Bonn nobles – besides the Elector – with an accomplished house orchestra was the Freiherr von Westerholt, who played bassoon himself. His son Wilhelm was a talented flutist and his daughter Maria Anna was a brilliant keyboardist – and a student of the lad Beethoven.

The Westerholt family certainly got a brilliant showpiece from the young composer. The opening Allegro begins with a figurative bang, the ascending "Mannheim rocket" figure than fashionable to indicate brilliance and verve. The keyboard part is full of florid, high-energy passagework, much of it echoed by the wind instruments. The development section of this sonata form movement begins in the minor dominant, with a motif that had been introduced by the bassoon. While operating within the Classical conventions of the time, Beethoven flexes the kind of motivic muscle that would become characteristic, with off-beat accents and frequent abrupt shifts in dynamics and character.

The slow movement is a pathos-laden operatic affair in the tonic minor, although Beethoven soon shifts it to the relative major key, which he subsequently sweetens further with a triplet lilt. A dark, chromatic modulation brings the music back to the minor mode, and an enigmatically and dramatically gapped close that – spoiler alert! – doesn't really end, but instead sets up the final variations.

These are expectedly blithe and showy. The courtly little binary theme is elemental enough to allow expansive figural variation, with a second-half shift to minor mode that is a familiar tactic by this point. The seven variations include solos for the wind instruments and much etude-like keyboard display. A minor mode variation is almost obligatory in contemporary variation sets, but Beethoven raises the dramatic bar here with a shift in meter as well, and then gives the tune little shoves off the beat. For his finale, Beethoven kicks the tempo up to Allegro (from Andante) and continues the ornamental variation, ending with an athletic little coda that is a miniature model for what will become a signature device.

— John Henken