Piano sonatas (Beethoven)
Ludwig van Beethoven wrote his 32 piano sonatas between 1795 and 1822. Although originally not intended to be a meaningful whole, as a set they compose one of the most important collections of works in the history of music. Hans von Bülow called them "The New Testament" of the piano literature (Johann Sebastian Bach's "The Well-Tempered Clavier" being "The Old Testament").
Piano Sonata No. 27 (Beethoven)
Beethoven's previous piano sonata, popularly known as "Les Adieux", was composed almost five years prior to Op. 90. Beethoven's autograph survives and is dated 16 August. The sonata was published almost a year later, in June 1815, by S. A. Steiner, after a few corrections were made by Beethoven. Beethoven's letter to Prince Moritz von Lichnowsky, sent in September 1814, explains Beethoven's dedication: