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 pedals
Beethoven took advantage of the ability of his piano to create a wide range of tone color in two of his piano works. In his Piano Concerto No. 4, Beethoven specifies the use of una corda, due corde, and tre corde. He calls for una corda, then "poco a poco due ed allora tutte le corde", gradually two and then all strings, in Sonata Op. 106.