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. 30 (Beethoven)
Work on Op. 109 can be traced back to early in 1820, even before Beethoven's negotiations with Adolf Schlesinger, the publisher of his last three sonatas. Recent research suggests that Friedrich Starke had asked Beethoven for a composition for his piano anthology "The Vienna Pianoforte School", and that Beethoven had interrupted work on the "Missa Solemnis". In the end, though, he offered Starke numbers 7–11 of the "Bagatelles, Op. 119".