A string quartet is a musical ensemble consisting of four string players - two violin players, a viola player and a cellist - or a musical composition written to be performed by such a group. The string quartet is one of the most prominent chamber ensembles in classical music; most major composers from the mid 18th century onwards having written string quartets.
The string quartet was developed into its present form by the Austrian composer Joseph Haydn, whose works in the 1750s established the ensemble as a group of four more-or-less equal partners. Since Haydn the string quartet has been considered a prestigious form: writing for four instruments with broadly similar characteristics both constrains and tests a composer's art. String quartet composition flourished in the Classical era: Wolfgang Amadeus Mozart and Ludwig van Beethoven each wrote a number of them. Many Romantic and early-twentieth-century composers composed string quartets, including Franz Schubert, Felix Mendelssohn, Robert Schumann, Johannes Brahms, Antonín Dvo?ák, Leo? Janá?ek and Claude Debussy. There was a slight lull in string quartet composition later in the 19th century, but it received a resurgence in the 20th century, with the Second Viennese School, Béla Bartók, Dmitri Shostakovich, Milton Babbitt and Elliott Carter producing highly regarded examples of the genre, and it remains an important and refined musical form.
The standard structure for a string quartet as established in the Classical era is four movements, with the first movement in Sonata form, Allegro, in the tonic key; a slow movement in a related key and a Minuet and Trio follow; and the fourth movement is often in Rondo form or Sonata rondo form, in the tonic key.
Some string quartets ensembles play together for many years and become established and promoted as an entity in a similar way to an instrumental soloist or an orchestra.
The early history of the string quartet is in many ways the history of Haydn's journey with the genre. Not that he composed the first quartet of all: before Haydn alighted on the genre there had been examples of divertimenti for two solo violins, viola and cello by Viennese composers such as Georg Christoph Wagenseil and Ignaz Holzbauer; and there had long been a tradition of performing orchestral works one instrument to a part. David Wyn Jones cites the widespread practice of four players, one to a part, playing works written for string orchestra, such as divertimenti and serenades, there being no separate (fifth) contrabass part in string scoring before the 19th century. However, these composers showed no interest in exploring the development of the string quartet as a medium.
The origins of the string quartet can be further traced back to the Baroque trio sonata, in which two solo instruments performed with a continuo section consisting of a bass instrument (such as the cello) and keyboard. A very early example is a four-part sonata for string ensemble by Gregorio Allegri (1582-1652) that might be considered an important prototype. By the early 18th century, composers were often adding a third soloist; and moreover it became common to omit the keyboard part, letting the cello support the bass line alone. Thus when Alessandro Scarlatti wrote a set of six works entitled "Sonata à Quattro per due Violini, Violetta [viola], e Violoncello senza Cembalo" (Sonata for four instruments: two violins, viola, and cello without harpsichord), this was a natural evolution from the existing tradition.
Haydn is responsible for the string quartet in its now accepted form. Although he did not invent the combination of two violins, viola and cello, previous occurrences in chamber music were more likely due to circumstance rather than conscious design. The string quartet enjoyed no recognized status as an ensemble in the way that two violins with basso continuo - the so-called 'trio sonata' - had for more than a hundred years. Even the composition of Haydn's earliest string quartets owed more to chance than artistic imperative. During the 1750s, when the young composer was still working mainly as a teacher and violinist in Vienna, he would occasionally be invited to spend time at the nearby castle at Weinzierl of the music-loving Austrian nobleman Karl Joseph Weber, Edler von Fürnberg. There he would play chamber music in an ad hoc ensemble consisting of Fürnberg's steward, a priest and a local cellist, and when the Baron asked for some new music for the group to play, Haydn's first string quartets were born. It is not clear whether any of these works ended up in the two sets published in the mid-1760s and known as Haydn's Opp.1 and 2 ('Op.0' is a quartet included in some early editions of Op.1, and only rediscovered in the 1930s), but it seems reasonable to assume that they were at least similar in character.
Haydn's early biographer Georg August Griesinger tells the story thus:
The following purely chance circumstance had led him to try his luck at the composition of quartets. A Baron Fürnberg had a place in Weinzierl, several stages from Vienna, and he invited from time to time his pastor, his manager, Haydn, and Albrechtsberger (a brother of the celebrated contrapuntist Albrechtsberger) in order to have a little music. Fürnberg requested Haydn to compose something that could be performed by these four amateurs. Haydn, then eighteen years old, took up this proposal, and so originated his first quartet which, immediately it appeared, received such general approval that Haydn took courage to work further in this form.
Haydn went on to write nine other quartets around this time. These works were published as his Op. 1 and Op. 2; one quartet went unpublished, and some of the early "quartets" are actually symphonies missing their wind parts. They have five movements and take the form: fast movement, minuet and trio I, slow movement, minuet and trio II, and fast finale. As Ludwig Finscher notes, they draw stylistically on the Austrian divertimento tradition.
After these early efforts Haydn did not return to the string quartet for several years, but when he did so, it was to make a significant step in the genre's development. The intervening years saw Haydn begin his employment as Kapellmeister to the Esterhazy princes, for whom he was required to compose numerous symphonies and dozens of trios for violin, viola and the curious bass instrument called the baryton (played by Prince Nikolaus Esterhazy himself). The opportunities for experiment which both these genres offered Haydn perhaps helped him in the pursuit of the more advanced quartet style found in the eighteen works published in the early 1770s as Opp.9, 17 and 20. These are written in a form that became established as standard both for Haydn and for other composers. Clearly composed as sets, these quartets feature a four-movement layout having broadly conceived, moderately paced first movements and, in increasing measure, a democratic and conversational interplay of parts, close-knit thematic development, and skilful though often self-effacing use of counterpoint. The convincing realizations of the progressive aims of the Op.20 set of 1772, in particular, makes them the first major peak in the history of the string quartet. Certainly they offered to their own time state-of-the art models to follow for the best part of a decade; the teenage Mozart, in his early quartets, was among the composers moved to imitate many of their characteristics, right down to the vital fugues with which Haydn sought to bring greater architectural weight to the finales of nos. 2, 5 and 6.
After Op.20 it becomes harder to point to similar major jumps in the string quartet's development in Haydn's hands, though not due to any lack of invention or application on the composer's part. As Donald Tovey put it: "with Op.20 the historical development of Haydn's quartets reaches its goal; and further progress is not progress in any historical sense, but simply the difference between one masterpiece and the next."
That Haydn's string quartets were already "classics" that defined the genre by 1801 can be judged by Ignaz Pleyel's publication in Paris of a "complete" series that year, and the quartet's evolution as vehicle for public performance can be judged by Pleyel's ten-volume set of miniature scores intended for hearers rather than players - early examples of this genre of music publishing. Since Haydn's day the string quartet has been prestigious and considered one of the true tests of a composer's art. This may be partly because the palette of sound is more restricted than with orchestral music, forcing the music to stand more on its own rather than relying on tonal color; or from the inherently contrapuntal tendency in music written for four equal instruments.
Quartet composition flourished in the Classical era. Mozart, Beethoven and Schubert each composed a number of quartets: "Beethoven in particular is credited with developing the genre in an experimental and dynamic fashion, especially in his later series of quartets written in the 1820s up until his death. Their forms and ideas inspired and continue to inspire musicians and composers, such as Richard Wagner and Béla Bartók." Schubert's last musical wish was to hear Beethoven's Quartet in C♯ minor, Op. 131, which he did on 14 November 1828, just five days before his death. Upon listening to an earlier performance of this quartet, Schubert had remarked, "After this, what is left for us to write?" Wagner, when reflecting on Op. 131's first movement, said that it "reveals the most melancholy sentiment expressed in music". Of the late quartets, Beethoven cited his own favorite as Op. 131, which he saw as his most perfect single work.
Mendelssohn's six string quartets span the full range of his career, from 1828 to 1847; Schumann's three string quartets were all written in 1842 and dedicated to Mendelssohn, whose quartets Schumann had been studying in preparation, along with those of Haydn, Mozart and Beethoven. Several Romantic-era composers wrote only one quartet, while Antonín Dvo?ák wrote 14. In the modern era, the string quartet played a key role in the development of Arnold Schoenberg (who was the first to add a soprano in his String Quartet No. 2), Béla Bartók, and Dmitri Shostakovich especially. After the Second World War, some composers, such as Olivier Messiaen questioned the relevance of the string quartet and avoided writing them. However, from the 1960s onwards, many composers have shown a renewed interest in the genre. During his tenure as Master of the Queen's Music, Peter Maxwell Davies produced a set of ten entitled the Naxos Quartets (to a commission from Naxos Records) from 2001 to 2007. Margaret Jones Wiles composed over 50 string quartets. David Matthews has written eleven, and Robin Holloway both five quartets and six "quartettini".
A composition for four players of stringed instruments may be in any form. Quartets written in the classical period usually have four movements with a large-scale structure similar to that of a symphony:
Substantial modifications to the typical structure were already achieved in Beethoven's later quartets, and despite some notable examples to the contrary, composers writing in the twentieth century increasingly abandoned this structure.
Many other chamber groups can be seen as modifications of the string quartet:
Further expansions have also been produced such as the String octet by Mendelssohn. Notably, Schoenberg included a soprano in the last two movements of his second string quartet, composed in 1908. This instrumentation of adding a voice is succeeded by Milhaud, Ginastera, Ferneyhough, Davies and many others. Another variation on the traditional string quartet is the electric string quartet with players performing on electric instruments.
Some of the most notable works for string quartet include:
Whereas individual string players often group together to make ad hoc string quartets, others continue to play together for many years in ensembles which may be named after the first violinist (e.g. the Takács Quartet), a composer (e.g. the Borodin Quartet) or a location (e.g. the Budapest Quartet). Established quartets may undergo changes in membership whilst retaining their original name.