The piano Sonata No. 14 in c-sharp minor, op. 27 No. 2, also known as the Mondscheinsonate (Moonlight Sonata) is the fourteenth Beethoven piano Sonata and one of his most famous works. Especially the first part is very well known. Beethoven called it work like the previous Sonata quasi una Fantasia a piano Sonata (a Sonata that as fantasy feel). The play was dedicated to Countess Giulietta Guicciardi.
Pianist András Schiff says about this first part: "the name Moonlight is nonsense. The name is not given by Beethoven, but by poet and music critic Ludwig Rellstab (...), when he sat in a boat, on a beautiful evening at full moon. This recalled him to the first part of the c-sharp minor Sonata. So is a name coined, which has nothing to do with the poor Beethoven piano Sonata. But it is now, if with glue, stuck with it. "
The format of the piano Sonata is unusual because the first part not the sonata form has. A slow part, a scherzo-like part (the second part) and a fast finale are present, although here too the middle part in an unusual key, namely Des-large (it should be noted that this was a normal practice for Beethoven. In his Sonata in C major was the second section in E major, to resolve only if the dominant of the parallel minor of the tonic appears).