Sonata in A-flat major, Hob. XVI:46
The keyboard works of Haydn, like all of the vast amount of music he composed, reveal a gradual, deliberate, craftsmanly development over the course of his long career. The earliest pieces, written either for clavichord or harpsichord, were not even called sonatas, but rather, in the Baroque manner, designated as partitas or divertimentos. (Remember that Haydn was born in the high Baroque; he was 18 when Bach died.)
The present Sonata (originally a divertimento) shows Haydn fairly bursting out of the modest classical mold – circumspectly, of course. One notices first that the piece is written in a key (A-flat) with four flats, in contrast with a large number of the composer’s sonatas with no more than three accidentals in the key signature; a small point but significant. Then one is aware of the large quantity of notes throughout the measures, and the very many indications for notes to be ornamented. Both of those elements indicate the early origin of the work, despite its relatively high Hoboken number (from the standard catalogue of Haydn’s music). Also in the first movement, the second theme does not contrast with the first theme as is usually the case in later sonatas and which is a manner Haydn eventually adopted. Haydn’s development section is extremely athletic and brilliant, lending the first movement a virtuosic profile.
The extended second movement is stoically expressive even with its extensive ornamentation, and it provides a moving prelude to the hell-bent-for-speed last movement as only Haydn can do it.