One of the remarkable late sonatas written by Haydn right around 1790, when his life was about to change dramatically with the death of Nikolaus Esterhazy and his first trip to London. This sonata was definitely written in Austria, however.
First Movement: Andante con espressione
Haydn's many experiments with rondo-like forms led to this remarkable movement, which is essentially a double-variation set but cast in a distinctly rondo-ish style. The primary theme in C Major is subjected to numerous interesting variations (while never losing its identity), but contrasted with its own minor-key version which is also subjected to variations on its own. (Generally speaking, in a double variation set, one of the themes is considerably more varied than the other, but in the case of this sonata, both themes are given their own treatments.) Although one can point to other such double-variation movements in Haydn's work, especially using a parallel-key version of the main theme for the second of the melodies (Symphony No. 53, II and Symphony No. 103, II come to mind), this movement is almost unique amongst Haydn's solo keyboard works.
Second Movement: Presto
Sonata-rondo form was a product of the later Viennese Classical era; scholars are still debating whether Haydn or Mozart (or somebody else) should have priority of invention. It seems to have been in the air, so to speak. This perfectly-realized example of the idiom (in which the sections of a Rondo take on the characteristics of similar sections in sonata form, such as primary theme, secondary theme, and transitional passages), also combines Haydn's love for monothematic forms (i.e., those using one theme only). As a result, in its four-minute length it manages to be a tour de force of imaginative and skillful construction, truly one of the masterpieces of Haydn's keyboard output.