Clarinet Quintet in A major, K. 581

Composed in 1789 for the clarinettist Anton Stadler, Mozart's lifelong friend and fellow Mason, this quintet exploits the full tonal range of the basset clarinet — an instrument with an extended lower register that Stadler championed. The work is one of the most perfectly proportioned in the chamber repertoire: the opening Allegro glows with warm lyricism, the Larghetto is a duet of exquisite delicacy, the Menuetto has peasant-dance energy, and the finale is a set of variations of effortless charm. The clarinet writing descends unusually low, revealing a chalumeau register of velvety beauty. Together with the Brahms Op. 115, it stands at the apex of the clarinet quintet canon.