피아노 소나타 14번 (Piano Sonata no. 14 in C sharp minor, op. 27 no. 2, "Moonlight")

The Piano Sonata No. 14 in C♯ minor, marked Quasi una fantasia, Op. 27, No. 2, is a piano sonata by Ludwig van Beethoven, completed in 1801 and dedicated in 1802 to his pupil Countess Julie "Giulietta" Guicciardi. Although known throughout the world as the Moonlight Sonata (German: Mondscheinsonate), it was not Beethoven who named it so. The title "Moonlight Sonata'" was proposed in 1832, after the composer’s death, by the poet Ludwig Rellstab. The piece is one of Beethoven's most famous compositions for the piano, and was quite popular even in his own day. Beethoven wrote the Moonlight Sonata around the age of 30, after he had finished with some commissioned work; there is no evidence that he was commissioned to write this sonata.