Ludwig van Beethoven's opus 27 no. 2 is the Piano Sonata No. 14 in C sharp minor "Quasi una fantasia" (Italian: Like a fantasy), popularly known as the Moonlight Sonata.
Beethoven wrote this sonata in 1801 and dedicated it to the 17-year-old Countess Giulietta Guicciardi, with whom he was (or, according to some accounts, had been) in love. In 1832, several years after Beethoven's death, the poet Ludwig Rellstab compared the music to moonlight shining on Lake Lucerne. Since then, it has been known as the Moonlight Sonata.
The Sonata has three movements:
The second movement is a relatively conventional minuet and trio, a moment of relative calm written in D flat major. This key signature is enharmonically equivalent to C sharp major, that is, the tonic major for the work as a whole. The slightly odd sound of the first eight bars seems to be the result of the minuet starting in the "wrong" key; i.e. the dominant key of A flat major. The music settles into D flat only in the second phrase, bars 5-8.
The stormy final movement, in sonata form, is the weightiest of the three, reflecting an experiment of Beethoven's (also carried out in the companion sonata, Opus 27 no. 1 and later on in Opus 101) of placing the most important movement of a sonata last. The writing has many fast arpeggios and strongly accented notes, and an effective performance demands flamboyant and skillful playing. Beethoven was known to break hammers and strings when he played, and it is easy to imagine this happening when he performed this movement.
The musical dynamic that predominates in the third movement is in fact piano. It seems that Beethoven's heavy use of sforzando notes, together with just a few strategically located fortissimo passages, creates the sense of a very powerful sound in spite of the overall dynamic.
The Moonlight Sonata is one of Beethoven's most popular works, and it is frequently performed and recorded.
At the opening of the work, Beethoven included a written direction that the damper pedal should be depressed for the entire duration of the first movement. The Italian reads: "Si deve suonare tutto questo pezzo delicatissimamente e senza sordino" ("The entire piece must be played as delicately as possible and without dampers."). Beethoven's instruction cannot feasibly be respected by pianists playing modern instruments without creating an unpleasantly dissonant sound, and most pianists today try to achieve an effect similar to what Beethoven asked for using pedal changes only where necessary to avoid excessive dissonance. For instance, the score posted at the external link given below does include pedal marks throughout the first movement; these are the work of a 20th century editor, meant to facilitate performance on a modern instrument.
Exponents of authentic performance, using restored or replicated pianos of the kind Beethoven knew, have performed the work respecting Beethoven's original direction.
Book:
The Moonlight Sonata is discussed in Charles Rosen's book Beethoven's Piano Sonatas: A Short Companion (Yale University Press, 2002, ISBN 0300090706).
External link:
The William and Gayle Cook Music Library at the Indiana University School of Music has posted the score for the sonata.Beethoven's pedal mark