B.’s two sonatas (really sonatinas) are misnumbered: they were written at around the same time as the 3rd and 4th sonatas, but were published a lot later because B. never intended that they be published (we’ve got his brother to thank that these sonatas are known at all.) Both sonatas are small, two-movement, unassuming pieces, unabashedly classical in style, and constructed rather straightforwardly for (in all likelihood) some of B.’s friends (or their children).
Which is not to say they are not wonderful pieces. The 19th sonata has a particularly moving first movement, with a starkly doleful first theme and a lyrical second. The second movement is struck through with little dashes of humour, starting from its rather long upbeat. And though it is not a radically new or innovative, the 19th perfectly written for what it is: an example of the classical two-movement form, concise, graceful, with a naturalness of expression that only the greatest classical composers ever achieved.
MVT I, Anda