The Piano Sonata No. 14 in C♯ minor, labeled Quasi una fantasia, Op. 27, No. 2, is a piano sonata composed by Ludwig van Beethoven. It was finished in 1801 and given to his student, Countess Julie "Giulietta" Guicciardi, in 1802. Although it is widely known today as the Moonlight Sonata (Mondscheinsonate in German), Beethoven did not name it this way. The title Moonlight Sonata was first used in 1832, after Beethoven’s death, by the poet Ludwig Rellstab.

This piece is one of Beethoven’s most famous piano works and was very popular during his lifetime. Beethoven wrote the Moonlight Sonata when he was about 30 years old, after completing some other commissioned pieces. There is no evidence that he was asked to write this sonata specifically.

Names

The first version of the piece is titled Sonata quasi una fantasia ("sonata resembling a fantasy"), the same name as its companion piece, Op. 27, No. 1. Grove Music Online explains the Italian title as "sonata in the manner of a fantasy." The subtitle helps listeners understand that, even though the piece is a sonata, it feels free and spontaneous, like a fantasy.

Many sources say the nickname "Moonlight Sonata" came from Ludwig Rellstab, a German music critic and poet, who compared the first movement to moonlight shining on Lake Lucerne. This information comes from Wilhelm von Lenz, a musicologist who wrote in 1852: "Rellstab compared this work to a boat traveling by moonlight to distant parts of Lake Lucerne in Switzerland. The nickname Mondscheinsonate, which caused excitement in Germany twenty years ago, has no other origin." If taken literally, "twenty years" would mean the nickname started after Beethoven died. However, Rellstab made his comment about the first movement in a story called Theodor that he published in 1824. In it, he wrote: "The lake rests in soft moonlight, gentle waves touch the dark shore; shadowy mountains rise and block the holy place from the world; ghostly swans glide quietly on the water, and an Aeolian harp plays mysterious, sorrowful tones from ruins." Rellstab did not mention Lake Lucerne, which seems to have been Lenz's own addition. Rellstab met Beethoven in 1825, so it was possible Beethoven heard about the moonlight comparison, though the nickname may not have been used until later.

By the late 1830s, the name Mondscheinsonate appeared in German publications, and "Moonlight Sonata" in English ones. By the end of the nineteenth century, the piece was widely known by that name.

Some critics have criticized the nickname "Moonlight" for being too emotional and not accurate. They have called it "a misleading way to describe a movement that feels like a funeral march" and "absurd." Other critics have supported the nickname, saying it is evocative or matches their view of the music. Compton Mackenzie, founder of Gramophone, said the nickname was harmless, adding that "it is silly for strict critics to be upset about Rellstab's comment," and that "these critics miss the fact that the nickname would have been forgotten if the public had not liked the idea of moonlight in the music." Musicologist Donald Francis Tovey believed the nickname was fitting for the first movement but not for the others.

Carl Czerny, a student of Beethoven, described the first movement as "a ghost scene, where a sad, ghostly voice sounds from far away."

Franz Liszt described the second movement as "a flower between two abysses."

Form

Although there is no direct evidence explaining why Beethoven named both Op. 27 works Sonata quasi una fantasia, it is notable that the structure of this sonata does not follow the traditional Classical period movement order of fast–slow–[fast]–fast. Instead, the sonata has an end-weighted structure, with the faster music delayed until the third movement. German critic Paul Bekker wrote: "The first movement gave the work a clear character from the start, which later movements could add to but not change. Beethoven opposed this fixed quality in the first movement. He wanted an introduction, not a clear statement."

The sonata has three movements:

The first movement, in C♯ minor and alla breve, is written in a modified sonata-allegro form. Donald Francis Tovey warned performers to avoid playing this movement "on a quaver standard like a slow 8."

The movement begins with an octave in the left hand and a triplet pattern in the right. A melody, described by Hector Berlioz as a "lamentation," is played by the left hand against an accompanying triplet rhythm in the right. The movement is played pianissimo (pp) or "very quietly," and the loudest it reaches is piano (p) or "quietly."

The adagio sostenuto tempo has deeply moved many listeners. Berlioz wrote that it "is one of those poems that human language does not know how to qualify." Beethoven’s student Carl Czerny described it as "a nocturnal scene, in which a mournful ghostly voice sounds from the distance." The movement was very popular during Beethoven’s time, even frustrating the composer, who told Czerny, "Surely I've written better things."

In his book Beethoven's Pianoforte Sonatas, pianist Edwin Fischer suggested that this movement is based on Mozart’s "Ah soccorso! Son tradito" from Don Giovanni, which follows the Commendatore’s murder. Fischer claimed to have found a sketch in Beethoven’s handwriting of Mozart’s music (transposed to C♯ minor) in the archives of the Wiener Musikverein. He wrote, "In any case, there is no romantic moonlight in this movement: it is rather a solemn dirge."

The second movement is a relatively conventional minuet in triple time, with the first section not repeated. It is written in D♭ major, the more easily notated enharmonic equivalent of C♯ major, the parallel major of the sonata’s key, C♯ minor. Most of the movement is played piano (p), but a few sforzandos (sfz) and fortepianos (fp) help maintain its cheerful tone. It is the shortest movement and has been called the "less popular" interlude between the first and third movements. Franz Liszt reportedly described the second movement as "a flower between two chasms."

The final movement (C♯ minor), in sonata form and common time, is the most substantial of the three. It reflects an experiment by Beethoven, also used in the companion sonata Op. 27, No. 1, and later in Op. 101, where the most important movement is placed last. The writing includes fast arpeggios, broken chords, strongly accented notes, and fast alberti bass sequences in both hands. A successful performance requires lively, skilled playing and great stamina, making it significantly more technically demanding than the first and second movements.

Charles Rosen wrote of the final movement, "it is the most unbridled in its representation of emotion. Even today, two hundred years later, its ferocity is astonishing."

Beethoven’s frequent use of sforzando (sfz) notes, combined with a few strategically placed fortissimo (ff) passages, creates the impression of a powerful sound despite the overall use of piano (p) markings.

Beethoven's pedal mark

At the start of the first movement, Beethoven wrote a direction in Italian: "Si deve suonare tutto questo pezzo delicatissimamente e senza sordino" ("This whole piece must be played with great care and without damper"). To follow this instruction, musicians use the sustain pedal throughout the movement, or they press and release it again as the music changes.

Modern pianos have a longer sustain time than the pianos Beethoven used. This means that keeping the sustain pedal pressed continuously can create a sound with clashing notes. In contrast, musicians who use older pianos or modern instruments designed to mimic historical ones can follow Beethoven’s instruction more closely.

For performances on modern pianos, several methods are suggested:

• One method is to press and release the sustain pedal at specific times to avoid clashing sounds. This is shown in the Ricordi edition of the sonata, which includes pedal markings.
• A technique called half-pedaling, where the pedal is pressed only halfway, is often used to copy the shorter sustain of early 19th-century pianos. Musician Charles Rosen suggested using this method or releasing the pedal slightly late.
• Musician Joseph Banowetz proposed using the sostenuto pedal. The pianist presses the lowest bass notes silently before starting the movement, then uses the sostenuto pedal to keep those notes vibrating while playing. This allows the low notes to create a soft, blended sound.

Influence on later composers

The C♯ minor sonata, especially its third movement, is believed to have inspired Frédéric Chopin's Fantaisie-Impromptu. The Fantaisie-Impromptu is considered a tribute to Beethoven. It shows the key relationships, chord structures, and shares some musical passages from the sonata's three movements. Ernst Oster wrote: "Through the Fantaisie-Impromptu, we can recognize which features of the C♯ minor Sonata influenced Chopin. Chopin seems to guide us, pointing to a section of the sonata and saying, 'This is important. Pay attention to this example.' The Fantaisie-Impromptu may be the only instance where one great composer reveals, through his own work, what he hears in the music of another great composer."

Carl Bohm's "Meditation," Op. 296, for violin and piano, adds a violin melody to the first movement of Beethoven's sonata without changing the original music.

Dmitri Shostakovich used the first movement of the sonata in his Viola Sonata, Op. 147 (1975), his final composition. The third movement, which includes a short quotation from the sonata, is titled "Adagio in memory of Beethoven."