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'" arose via imagery later proposed by the poet Ludwig Rellstab, which resonated with listeners. The piece is one of Beethoven's most famous compositions for the piano, and was quite popular even in his own day.