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. 31 (Beethoven)
In the summer of 1819 Moritz Schlesinger, from the Schlesinger firm of music publishers based in Berlin, met Beethoven and asked to purchase some compositions. After some negotiation by letter, and despite the publisher's qualms about Beethoven's retaining the rights for publication in England and Scotland, Schlesinger agreed to purchase 25 songs for 60 ducats and three piano sonatas at 90 ducats (Beethoven had originally asked 120 ducats for the sonatas). In May 1820 Beethoven agreed, the songs (Op. 108) already being available, and he undertook to deliver the sonatas within three months. These three sonatas are the ones now known as Opp. 109–111.