Issued early in 1780 with the C minor, No 20, the five sonatas Nos 35–39 inaugurated Haydn’s long relationship with the Viennese publisher Artaria. They were dedicated to the talented sisters Franziska and Maria Katherina von Auenbrugger, whose playing drew the admiration of both Leopold Mozart—never one to dish out compliments lightly—and Haydn himself. Designated, for the first time, ‘for harpsichord, or forte-piano’, and often calling for the dynamic flexibility only possible on the newer instrument, these ‘Auenbrugger’ sonatas are as disparate in style as the 1776 set (Nos 27–32). The finest is No 36, in the rare and ‘extreme’ key of C sharp minor, though unlike the unremittingly serious C minor Sonata, No 20, it juxtaposes severe and ‘popular’ styles. The first movement develops the two limbs of its sole theme—a brusque forte unison and a soft, ‘pathetic’ response—with an almost Beethovenian trenchancy. Coming between this and the finale, a slow minuet of exquisite, refined melancholy with an assuaging C sharp major trio, the perky A major Scherzando (whose tune Haydn pilfered for Sonata No 39) seems like a facetious interloper.
from notes by Richard Wigmore © 2012