Beethoven’s four-movement Sonata in A-flat major op. 26 belongs to his most popular works. It is dedicated to Prince Lichnowsky, one of his most generous patrons and the dedicatee of, for example, the Grande Sonate pathétique op. 13 and Symphony No. 2 op. 35. The work’s initial drafts date from 1800–01; it was first published in March 1802.

This demanding sonata is highly varied in its form: it begins with a set of variations and contains the famous Marcia funebre sulla morte d’un Eroe as its...