Ludwig van Beethoven's Piano Sonata No. 23 in F minor, Op. 57 (colloquially known as the Appassionata) is a piano sonata. It is considered one of the three great 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.
Unlike the early Sonata No. 8, Pathétique, the Appassionata was not named during the composer's lifetime, but was so labeled in 1838 by the publisher of a four-hand arrangement of the work.