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 Trios, Op. 70 (Beethoven)
These pieces are representative of Beethoven's "Middle" stylistic period, which went from roughly 1803 to 1812, and which included many of his most famous works. Beethoven wrote the two piano trios while spending the summer of 1808 in Heiligenstadt, Vienna, where he had completed his Symphony No. 5 the previous summer. He wrote the two trios immediately after finishing his "Sinfonia pastorale", Symphony No. 6. This was a period of uncertainty in Beethoven's life, in particular because he had no dependable source of income at the time.