Beethoven's piano sonatas Opus 90, 101, and 106 form a bridge between his earlier works and the late sonatas (Op. 109-111) of the 1820s. Composed during the 1810s, they constitute an unofficial trilogy. Although written in different keys, they offer a captivating diversity. A fluid transition can be observed between the individual works, with a steady increase in scope and technical demands. Nevertheless, each sonata retains its own distinct character.
The E minor Sonata Op. 90 was composed in the summer of 1814. Initially, there was some confusion regarding its dedication to Count Moritz Lichnowsky. Anton Schindler romanticized the idea that it reflected the Count's affection for his second wife, even though his first wife was still alive. Composed in the patriotic spirit of the age following Napoleon's defeat, the movements bear German titles.
The Sonata in A major, Op. 101, is generally considered the prelude to Beethoven's "late" creative period, characterized by more complex structures and increased polyphony. As in Opus 90, Beethoven attempted to introduce German expressions instead of the usual Italian ones. He dedicated the composition, completed between 1815 and 1816, to a close friend.
The Sonata in B-flat major, Op. 106, known as the "Hammerklavier," was begun in 1817 and published in 1819. Dedicated to his patron, Archduke Rudolph, it demonstrates Beethoven's artistic consummate achievement. This important sonata is considered the pinnacle of his piano output. Beethoven arranged for publications in both London and Vienna, recommending a simplified version for the British market. The first movement, often nicknamed the "Hammerklavier Sonata," impresses with its symphonic character and demanding tempo.