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. 14 (Beethoven)
The piece is one of Beethoven's most popular compositions for the piano, and it was a popular favorite even in his own day. Beethoven wrote the "Moonlight Sonata" in his early thirties, after he had finished with some commissioned work; there is no evidence that he was commissioned to write this sonata.