music Music is the arrangement of sound to create some combination of Musical form, form, harmony, melody, rhythm, or otherwise Musical expression, expressive content. Music is generally agreed to be a cultural universal that is present in all hum ...

, the opus number is the "work number" that is assigned to a

musical composition Musical composition can refer to an Originality, original piece or work of music, either Human voice, vocal or Musical instrument, instrumental, the musical form, structure of a musical piece or to the process of creating or writing a new pie ...

, or to a set of compositions, to indicate the

chronological order Chronology (from Latin , from Ancient Greek , , ; and , ''-logia'') is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of events. It is also "the determination of t ...

of the

composer A composer is a person who writes music. The term is especially used to indicate composers of Western classical music, or those who are composers by occupation. Many composers are, or were, also skilled performers of music. Etymology and def ...

's publication of that work. Opus numbers are used to distinguish among compositions with similar titles; the word is abbreviated as "Op." for a single work, or "Opp." when referring to more than one work. Opus numbers do not necessarily indicate chronological order of composition. For example, posthumous publications of a composer's

juvenilia Juvenilia are literary, musical or artistic works produced by authors during their youth. Written juvenilia, if published at all, usually appear as retrospective publications, some time after the author has become well known for later works. Bac ...

are often numbered after other works, even though they may be some of the composer's first completed works. To indicate the specific place of a given work within a

music catalogue This article gives an overview of various catalogues of classical compositions that have come into general use. Opus numbers While the opus numbering system has long been the standard manner in which individual compositions are identified and ref ...

, the opus number is paired with a

cardinal number In mathematics, a cardinal number, or cardinal for short, is what is commonly called the number of elements of a set. In the case of a finite set, its cardinal number, or cardinality is therefore a natural number. For dealing with the cas ...

; for example,

Beethoven Ludwig van Beethoven (baptised 17 December 177026 March 1827) was a German composer and pianist. He is one of the most revered figures in the history of Western music; his works rank among the most performed of the classical music repertoire ...

's Piano Sonata No. 14 in C-sharp minor (1801, nicknamed ''Moonlight Sonata'') is "Opus 27, No. 2", whose work-number identifies it as a companion piece to "Opus 27, No. 1" ( Piano Sonata No. 13 in E-flat major, 1800–01), paired in same opus number, with both being subtitled ''Sonata quasi una Fantasia'', the only two of the kind in all of Beethoven's 32 piano sonatas. Furthermore, the ''Piano Sonata, Op. 27 No. 2, in C-sharp minor'' is also catalogued as "Sonata No. 14", because it is the fourteenth

sonata In music a sonata (; pl. ''sonate'') literally means a piece ''played'' as opposed to a cantata (Latin and Italian ''cantare'', "to sing"), a piece ''sung''. The term evolved through the history of music, designating a variety of forms until th ...

composed by Ludwig van Beethoven. Given composers' inconsistent or non-existent assignment of opus numbers, especially during the

Baroque The Baroque ( , , ) is a Western Style (visual arts), style of Baroque architecture, architecture, Baroque music, music, Baroque dance, dance, Baroque painting, painting, Baroque sculpture, sculpture, poetry, and other arts that flourished from ...

(1600–1750) and the Classical (1750–1827) eras,

musicologists Musicology is the academic, research-based study of music, as opposed to musical composition or performance. Musicology research combines and intersects with many fields, including psychology, sociology, acoustics, neurology, natural sciences, f ...

have developed other catalogue-number systems; among them the ''

Bach-Werke-Verzeichnis The (, ; BWV) is a Catalogues of classical compositions, catalogue of compositions by Johann Sebastian Bach. It was first published in 1950, edited by Wolfgang Schmieder. The catalogue's second edition appeared in 1990 and the third edition in ...

'' (BWV-number) and the '' Köchel-Verzeichnis'' (K- and KV-numbers), which enumerate the works of

Johann Sebastian Bach Johann Sebastian Bach (German: Help:IPA/Standard German, �joːhan zeˈbasti̯an baχ ( – 28 July 1750) was a German composer and musician of the late Baroque music, Baroque period. He is known for his prolific output across a variety ...

and

Wolfgang Amadeus Mozart Wolfgang Amadeus Mozart (27 January 1756 – 5 December 1791) was a prolific and influential composer of the Classical period (music), Classical period. Despite his short life, his rapid pace of composition and proficiency from an early age ...

, respectively.

Etymology

In the classical period, the Latin word ''opus'' ("work", "labour"), plural ''opera'', was used to identify, list, and catalogue a work of art. By the 15th and 16th centuries, the word ''opus'' was used by Italian composers to denote a specific musical composition, and by German composers for collections of music. In compositional practice, numbering musical works in chronological order dates from 17th-century Italy, especially

Venice Venice ( ; ; , formerly ) is a city in northeastern Italy and the capital of the Veneto Regions of Italy, region. It is built on a group of 118 islands that are separated by expanses of open water and by canals; portions of the city are li ...

. In common usage, the word ''opus'' is used to describe the best work of an artist with the term ''

magnum opus A masterpiece, , or ; ; ) is a creation that has been given much critical praise, especially one that is considered the greatest work of a person's career or a work of outstanding creativity, skill, profundity, or workmanship. Historically, ...

''. In Latin, the words ''opus'' (singular) and ''opera'' (plural) are related to the words ''opera'' (singular) and ''operae'' (plural), which gave rise to the Italian words ''opera'' (singular) and ''opere'' (plural), likewise meaning "work". In contemporary English, the word ''opera'' has specifically come to denote the dramatic musical genres of

opera Opera is a form of History of theatre#European theatre, Western theatre in which music is a fundamental component and dramatic roles are taken by Singing, singers. Such a "work" (the literal translation of the Italian word "opera") is typically ...

ballet Ballet () is a type of performance dance that originated during the Italian Renaissance in the fifteenth century and later developed into a concert dance form in France and Russia. It has since become a widespread and highly technical form of ...

, which were developed in Italy.''Oxford English Dictionary'', s.v.
opera, n. 1
,
opera, n. 2
As a result, the plural ''opera'' of ''opus'' tends to be avoided in English. In other languages such as German, however, it remains common.

Early usage

In the arts, an opus number usually denotes a work of

, a practice and usage established in the seventeenth century when composers identified their works with an opus number. In the eighteenth century, publishers usually assigned opus numbers when publishing groups of like compositions, usually in sets of three, six or twelve compositions. Consequently, opus numbers are not usually in chronological order, unpublished compositions usually had no opus number, and numeration gaps and sequential duplications occurred when publishers issued contemporaneous editions of a composer's works, as in the sets of

string quartet The term string quartet refers to either a type of musical composition or a group of four people who play them. Many composers from the mid-18th century onwards wrote string quartets. The associated musical ensemble consists of two Violin, violini ...

s by

Joseph Haydn Franz Joseph Haydn ( ; ; 31 March 173231 May 1809) was an Austrian composer of the Classical period (music), Classical period. He was instrumental in the development of chamber music such as the string quartet and piano trio. His contributions ...

(1732–1809) and

Ludwig van Beethoven Ludwig van Beethoven (baptised 17 December 177026 March 1827) was a German composer and pianist. He is one of the most revered figures in the history of Western music; his works rank among the most performed of the classical music repertoire ...

(1770–1827); Haydn's Op. 76, the Erdödy quartets (1796–97), comprises six discrete quartets consecutively numbered Op. 76 No. 1 – Op. 76 No. 6; whilst Beethoven's Op. 59, the Rasumovsky quartets (1805–06), comprises String Quartet No. 7, String Quartet No. 8, and String Quartet No. 9.

19th century to date

From about 1800, composers usually assigned an opus number to a work or set of works upon publication. After approximately 1900, they tended to assign an opus number to a composition whether published or not. However, practices were not always perfectly consistent or logical. For example, early in his career, Beethoven selectively numbered his compositions (some published without opus numbers), yet in later years, he published early works with high opus numbers. Likewise, some posthumously published works were given high opus numbers by publishers, even though some of them were written early in Beethoven's career. Since his death in 1827, the un-numbered compositions have been cataloged and labeled with the German acronym WoO (''Werk ohne Opuszahl''), meaning "work without opus number"; the same has been done with other composers who used opus numbers. (There are also other catalogs of Beethoven's works – see

Catalogues of Beethoven compositions The catalogues of Beethoven compositions are all of the different ways in which the musical compositions by Ludwig van Beethoven have been organized by researchers into his music. The problem Most of Beethoven's best known works were published wi ...

.) The practice of enumerating a posthumous opus ("Op. posth.") is noteworthy in the case of

Felix Mendelssohn Jakob Ludwig Felix Mendelssohn Bartholdy (3 February 18094 November 1847), widely known as Felix Mendelssohn, was a German composer, pianist, organist and conductor of the early Romantic music, Romantic period. Mendelssohn's compositions inc ...

(1809–47); after his death, the heirs published many compositions with opus numbers that Mendelssohn did not assign. In life, he published two

symphonies A symphony is an extended musical composition in Western classical music, most often for orchestra. Although the term has had many meanings from its origins in the ancient Greek era, by the late 18th century the word had taken on the meaning c ...

( Symphony No. 1 in C minor, Op. 11; and Symphony No. 3 in A minor, Op. 56), furthermore he published his symphony-cantata ''

Lobgesang ''Lobgesang'' (''Hymn of Praise''), Op. 52 ( MWV A 18), is an 11-movement "Symphony-Cantata on Words of the Holy Bible for Soloists, Choir and Orchestra" by Felix Mendelssohn. After the composer's death it was published as his Symphony No. 2 i ...

'', Op. 52, which was posthumously counted as his Symphony No. 2; yet, he chronologically wrote symphonies between symphonies Nos. 1 and 2, which he withdrew for personal and compositional reasons; nevertheless, the Mendelssohn heirs published (and cataloged) them as the '' Italian'' Symphony No. 4 in A major, Op. 90, and as the '' Reformation'' Symphony No. 5 in D major and D minor, Op. 107. While many of the works of

Antonín Dvořák Antonín Leopold Dvořák ( ; ; 8September 18411May 1904) was a Czech composer. He frequently employed rhythms and other aspects of the folk music of Moravia and his native Bohemia, following the Romantic-era nationalist example of his predec ...

(1841–1904) were given opus numbers, these did not always bear a logical relationship to the order in which the works were written or published. To achieve better sales, some publishers, such as N. Simrock, preferred to present less experienced composers as being well established, by giving some relatively early works much higher opus numbers than their chronological order would merit. In other cases, Dvořák gave lower opus numbers to new works to be able to sell them to other publishers outside his contract obligations. This way it could happen that the same opus number was given to more than one of his works. Opus number 12, for example, was assigned, successively, to five different works (an opera, a

concert overture Overture (from French ''ouverture'', "opening") is a music instrumental introduction to a ballet, opera, or oratorio in the 17th century. During the early Romantic era, composers such as Beethoven and Mendelssohn composed overtures which were ...

, a string quartet, and two unrelated piano works). In other cases, the same work was given as many as three different opus numbers by different publishers. The sequential numbering of his symphonies has also been confused: (a) they were initially numbered by order of publication, not composition; (b) the first four symphonies to be composed were published after the last five; and (c) the last five symphonies were not published in order of composition. The ''

New World Symphony New or NEW may refer to: Music * New, singer of K-pop group The Boyz * ''New'' (album), by Paul McCartney, 2013 ** "New" (Paul McCartney song), 2013 * ''New'' (EP), by Regurgitator, 1995 * "New" (Daya song), 2017 * "New" (No Doubt song), 19 ...

'' originally was published as No. 5, later was known as No. 8, and definitively was renumbered as No. 9 in the critical editions published in the 1950s. Other examples of composers' historically inconsistent opus-number usages include the cases of

César Franck César Auguste Jean Guillaume Hubert Franck (; 10 December 1822 – 8 November 1890) was a French Romantic music, Romantic composer, pianist, organist, and music teacher born in present-day Belgium. He was born in Liège (which at the time of h ...

(1822–1890),

Béla Bartók Béla Viktor János Bartók (; ; 25 March 1881 – 26 September 1945) was a Hungarian composer, pianist and ethnomusicologist. He is considered one of the most important composers of the 20th century; he and Franz Liszt are regarded as Hunga ...

(1881–1945), and

Alban Berg Alban Maria Johannes Berg ( ; ; 9 February 1885 – 24 December 1935) was an Austrian composer of the Second Viennese School. His compositional style combined Romantic lyricism with the twelve-tone technique. Although he left a relatively sma ...

(1885–1935), who initially numbered, but then stopped numbering their compositions.

Carl Nielsen Carl August Nielsen (; 9 June 1865 – 3 October 1931) was a Danish composer, conductor, and violinist, widely recognized as his country's most prominent composer. Brought up by poor yet musically talented parents on the island of Funen, he d ...

(1865–1931) and

Paul Hindemith Paul Hindemith ( ; ; 16 November 189528 December 1963) was a German and American composer, music theorist, teacher, violist and conductor. He founded the Amar Quartet in 1921, touring extensively in Europe. As a composer, he became a major advo ...

(1895–1963) were also inconsistent in their approaches.

Sergei Prokofiev Sergei Sergeyevich Prokofiev; alternative transliterations of his name include ''Sergey'' or ''Serge'', and ''Prokofief'', ''Prokofieff'', or ''Prokofyev''. , group=n ( – 5 March 1953) was a Russian composer, pianist, and conductor who l ...

(1891–1953) was consistent and assigned an opus number to a composition ''before'' composing it; at his death, he left fragmentary and planned, but numbered, works. In revising a composition, Prokofiev occasionally assigned a new opus number to the revision; thus Symphony No. 4 is two thematically related but discrete works: Symphony No. 4, Op. 47, written in 1929; and Symphony No. 4, Op. 112, a large-scale revision written in 1947. Likewise, depending upon the edition, the original version of Piano Sonata No. 5 in C major, is cataloged both as Op. 38 and as Op. 135. Despite being used in more or less normal fashion by a number of important early-twentieth-century composers, including

Arnold Schoenberg Arnold Schoenberg or Schönberg (13 September 187413 July 1951) was an Austrian and American composer, music theorist, teacher and writer. He was among the first Modernism (music), modernists who transformed the practice of harmony in 20th-centu ...

(1874–1951) and

Anton Webern Anton Webern (; 3 December 1883 – 15 September 1945) was an Austrian composer, conductor, and musicologist. His music was among the most radical of its milieu in its lyric poetry, lyrical, poetic concision and use of then novel atonality, aton ...

(1883–1945), opus numbers became less common in the later part of the twentieth century.

Other catalogues

To manage inconsistent opus-number usages – especially by composers of the

(1600–1750) and of the Classical (1720–1830) music eras –

have developed comprehensive and unambiguous catalogue number-systems for the works of composers such as: *

– catalogued with a BWV-number; a ''

'' number assigned by

Wolfgang Schmieder Wolfgang Schmieder (May 29, 1901 – November 8, 1990) was a German music librarian and musicologist. Schmieder was born in Bromberg (now Bydgoszcz, Poland).Eggebrecht, Hans. "Wolfgang Schmieder". ''Oxford Music Online''. 2001, https://doi.o ...

; however, older sources occasionally use S-numbers. *

Dietrich Buxtehude Dieterich Buxtehude (; born Diderich Hansen Buxtehude, ; – 9 May 1707) was a Danish composer and organist of the Baroque period, whose works are typical of the North German organ school. As a composer who worked in various vocal and instrumen ...

– catalogued with a BuxWV-number, a ''Buxtehude-Werke-Verzeichnis'' work number. * Marc-Antoine Charpentier – identified with an H-number per H.W. Hitchcock's comprehensive catalogue. *

Frédéric Chopin Frédéric François Chopin (born Fryderyk Franciszek Chopin; 1 March 181017 October 1849) was a Polish composer and virtuoso pianist of the Romantic period who wrote primarily for Piano solo, solo piano. He has maintained worldwide renown ...

– four catalogue systems have been applied: (i) B-numbers, by Maurice J. E. Brown; (ii) KK-numbers, by

Krystyna Kobylańska Krystyna Kobylańska (6 August 1925 in Brześć, Poland – 30 January 2009 in Milanówek, Poland) was a Polish musicologist, and former curator of the Fryderyk Chopin Society Museum in Warsaw. In 1977 (revised and translated to German in 1979) ...

; (iii) work-letters (A, C, D, E, P and S), by Józef Michał Chomiński; and (iv) WN-numbers in the

Chopin National Edition The National Edition of the Works of Fryderyk Chopin (), also known as the Chopin National Edition and the Polish National Edition, is an urtext edition of the complete works by Frédéric Chopin, aiming to present his output in its authentic fo ...

. Generally, these alternative music-catalogue systems identified compositions that the composer had not numbered. *

Claude Debussy Achille Claude Debussy (; 22 August 1862 – 25 March 1918) was a French composer. He is sometimes seen as the first Impressionism in music, Impressionist composer, although he vigorously rejected the term. He was among the most influe ...

– identified with an L-number, per

François Lesure François Lesure (23 May 1923 – 21 June 2001) was a French musicologist and librarian. He specialized in the life and works of Claude Debussy, but also wrote numerous bibliographies, studies in the sociology of music, and historical French top ...

's comprehensive catalogue. *

– identified with a B-number, per Jarmil Burghauser's comprehensive catalogue; which resolved the problems of different and duplicate opus-numbers assigned by the publishers of Dvořák's music. *

– identified with a Hob.-number, per the 1957 catalogue by

Anthony van Hoboken Anthony van Hoboken ( , ; 23 March 1887 – 1 November 1983) was a Dutch musical collector, bibliographer, and musicologist. He became especially well known for his scholarship on the music of Joseph Haydn and in particular for being the crea ...

. Although he assigned Hoboken-numbers to the

string quartets The term string quartet refers to either a type of musical composition or a group of four people who play them. Many composers from the mid-18th century onwards wrote string quartets. The associated musical ensemble consists of two violinists, a ...

, those compositions usually are known by opus numbers. *

Franz Liszt Franz Liszt (22 October 1811 – 31 July 1886) was a Hungarian composer, virtuoso pianist, conductor and teacher of the Romantic music, Romantic period. With a diverse List of compositions by Franz Liszt, body of work spanning more than six ...

– identified with an S-number, per the catalogue ''The Music of Liszt'' (1960), by

Humphrey Searle Humphrey Searle (26 August 1915 – 12 May 1982) was an English composer and writer on music. His music combines aspects of late Romanticism and modernist serialism, particularly reminiscent of his primary influences, Franz Liszt, Arnold Sch ...

. *

– identified either with a K-number or with a KV-number ('' Köchel-Verzeichnis nummer''), per the catalogue system of

Ludwig Ritter von Köchel Ludwig Ritter von Köchel (; born Ludwig Alois Friedrich Köchel; 14 January 1800 – 3 June 1877) was an Austrian musicologist, writer, composer, botanist, and publisher. He is best known for cataloguing the works of Mozart and originating the ...

. *

Niccolò Paganini Niccolò (or Nicolò) Paganini (; ; 27 October 178227 May 1840) was an Italian violinist and composer. He was the most celebrated violin virtuoso of his time, and left his mark as one of the pillars of modern violin technique. His 24 Caprices ...

– identified with an MS-number, per the 1982 ''Catalogo tematico'', by Moretti and Sorrento. *

Domenico Scarlatti Giuseppe Domenico Scarlatti (26 October 1685 – 23 July 1757) was an Italian composer. He is classified primarily as a Baroque music, Baroque composer chronologically, although his music was influential in the development of the Classical peri ...

– identified with three catalogue systems; (i) L-numbers, per the 1906 catalogue by Alessandro Longo; (ii) K-numbers and Kk-numbers, per the 1953 catalogue by

Ralph Kirkpatrick Ralph Leonard Kirkpatrick (; June 10, 1911April 13, 1984) was an American harpsichordist and musicologist, widely known for his chronological catalog of Domenico Scarlatti's keyboard sonatas as well as for his performances and recordings. Life an ...

; and (iii) P-numbers, per the 1967 catalogue by Giorgio Pestelli. *

Franz Schubert Franz Peter Schubert (; ; 31 January 179719 November 1828) was an Austrian composer of the late Classical period (music), Classical and early Romantic music, Romantic eras. Despite his short life, Schubert left behind a List of compositions ...

– identified with a D-number, per the catalogue of Otto Erich Deutsch. *

Maurice Ravel Joseph Maurice Ravel (7 March 1875 – 28 December 1937) was a French composer, pianist and conductor. He is often associated with Impressionism in music, Impressionism along with his elder contemporary Claude Debussy, although both composer ...

– identified with an M-number, per the 1986 catalogue by

Marcel Marnat Marcel Marnat (1933 – 17 December 2024) was a French musicologist, journalist and radio producer, responsible for the program of France Musique from 1978 to 1992. His works on Maurice Ravel and Giacomo Puccini have been regarded as landmark boo ...

. *

Henry Purcell Henry Purcell (, rare: ; September 1659 – 21 November 1695) was an English composer of Baroque music, most remembered for his more than 100 songs; a tragic opera, Dido and Aeneas, ''Dido and Aeneas''; and his incidental music to a version o ...

– identified with a Z-number, per the catalogue by Franklin B. Zimmerman. *

Antonio Vivaldi Antonio Lucio Vivaldi (4 March 1678 – 28 July 1741) was an Italian composer, virtuoso violinist, impresario of Baroque music and Roman Catholic priest. Regarded as one of the greatest Baroque composers, Vivaldi's influence during his lif ...

– identified with a RV number, per the Ryom-Verzeichnis catalogue by Peter Ryom. *

Gustav Holst Gustav Theodore Holst (born Gustavus Theodore von Holst; 21 September 1874 – 25 May 1934) was an English composer, arranger and teacher. Best known for his orchestral suite ''The Planets'', he composed many other works across a range ...

– identified with an H. catalogue number, per A Thematic Catalogue of Gustav Holst's Music by

Imogen Holst Imogen Clare Holst (; 12 April 1907 – 9 March 1984) was a British composer, arranger, conductor, teacher, musicologist, and festival administrator. The only child of the composer Gustav Holst, she is particularly known for her education ...

References

{{DEFAULTSORT:Opus Number Identifiers Musical terminology Music publishing

Etymology

Early usage

19th century to date

Other catalogues

See also

References