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. 23 (Beethoven)
Ludwig van Beethoven's Piano Sonata No. 23 in F minor, Op. 57 (colloquially known as the Appassionata, meaning "passionate" in Italian) is among the three famous piano sonatas of his middle period (the others being the "Waldstein", Op. 53 and "Les Adieux", Op. 81a); it was composed during 1804 and 1805, and perhaps 1806, and was dedicated to Count Franz von Brunswick. The first edition was published in February 1807 in Vienna.