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)
One of his greatest and most technically challenging piano sonatas, the "Appassionata" was considered by Beethoven to be his most tempestuous piano sonata until the twenty-ninth piano sonata (known as the "Hammerklavier"). 1803 was the year Beethoven came to grips with the irreversibility of his progressively deteriorating hearing.