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some problems with classical music catalogs

You may run into problems when you work with catalogs; watch out for them. Here a few of the most important problems and what you can do about them.

problems with opus numbers and work numbers

Because composers tend to publish their creations in the order in which they are written, sometimes people assume that opus numbers or work numbers indicate the sequence in which works are created and their approximate date of creation. To do this is a mistake because works are not always published in the order in which they were created and sometimes works are not published at all.

some problems with opus numbers—date and order of publication

Conceptually, an opus number establishes where a work belongs in the publication sequence, which is supposed to approximate the order in which they are created; but actually it neither establishes the order in which a composer's works are published nor the sequence in which they are created.

How can a work's publication sequence be put in doubt by an opus number?

  • Cases actually exist in which the composer assigns one opus number and the publisher assigns another to the same work. Which number are we to accept?
  • Sometimes works are published by more than one publishing house.
  • Some works are published in different countries or in different languages. Which one should be taken as the correct one?
  • Some works are distributed informally, not publicly published; they originally appeared only within an intimate circle of admirers or a coterie. Which distribution counts as publication?
  • Some works have been lost and rediscovered, then published years later, not in the order in which they originally should have been published. Works discovered after a composer's "complete" works have been published fall into this category.
  • Some works do not bear an opus number at all. Perhaps the composer just didn't bother to assign one. Perhaps one or more of his works were never published. Perhaps he has not written enough music to justify others keeping track of his individual compositions. Perhaps there is not enough interest in his output to warrant the effort of assigning numbers.
  • Works composed before circa 1800 when the practice of assigning numbers began were never assigned an opus number by anyone.
  • Many early works were never formally published at all. If such works bear a number today, it's probably a number that has been assigned by a cataloger who did research to confirm the order of composition or publication.

some problems with opus numbers—date and order of creation

Here are some examples of some problems that can arise by assuming that opus numbers are reliable indicators of creation sequences or dates:

  • Was a work by a composer finished before that composer's next work was started, or were both works written in an overlapping manner at the same time?
  • Was a second work started after a first work was begun, with the second work being finished before the first?
  • Was one work started and finished, then put away on a back shelf only to be dusted off years later?
  • If a composer revises a work, which version represents the original conception?
  • How do we assign opus numbers to multiple works that were lost and then rediscovered decades or centuries later?

These are only a few of the reasons why opus numbers can be unreliable indicators of a work's creation or publication order. Although useful in many instances, by themselves opus numbers may not be meaningful or may not exist at all.

problems with work numbers

Problems with work number sequencing and dating arise for the same reasons as do problems with opus number sequencing and dating; both are subject to the same kinds of errors. Errors in both produce similar pragmatic, conceptual, and aesthetic consequences. Although the sequence in which multiple works of the same type are written, such as two back-to-back symphonies, may or may not change even if new findings by historians result in a revision to their actual publication sequence, the two numbers are interrelated; one number should be always be consistent with the other.

Problems with opus numbers and work numbers

Mozart provides us with a multifold example of how opus numbers and work numbers can go awry:

Three of Mozart's piano concertosnumbers 11, 12, and 13—which today are listed as K.413-415, were composed in 1783 and were published in Vienna as Op. 4. The publisher had such success with these works, Mozart thereafter was incentivized to publish his piano concerto number 5, today listed as K.175. But the work known today as K.175—piano concerto No. 5—was penned ten years earlier, in 1773.

From this example, we see that:

Regarding opus number:

  • Although useful, an opus number does not necessarily represent the order in which a composer creates or publishes his work.
  • Opus number (Op. 4, in this case) can be a misleading indicator of the order of creation and/or publication.

Regarding work number:

  • Although useful, work numbers like 5, 11, 12, and 13 indicate the order in which a composer writes works of the same kind, whereas opus numbers or catalog numbers do not.
  • Numbers like 5, 11, 12, and 13 represent the sequence in which a composer creates works of the same kind (piano concertos in Mozart's case), but these are neither opus numbers nor catalog numbers; they are numbers that appear in catalogs, just as opus numbers appear in catalogs.

Regarding catalog number:

  • Catalog numbers such as K.175, K.413, K.414, and K.515 are the creation of a cataloger; they are more faithful indicators of the order in which a composer's works are written than opus or work numbers.
  • Catalog numbers accurately indicate where a given work fits in the sequence of the complete body of a composer's works and where one work of the same type fits with another, whereas opus numbers do not.

catalog naming exceptions

The standard symbol for a catalog is normally derived from one of these formulas:

  • The cataloger's initials.
  • The composer's initials.
  • A combination of the composer's initials and the cataloger's initials.
  • A combination of the cataloger's initials and the initials of the name of the catalog.
  • A combination of the composer's initials and the name of the catalog.
  • The name of the catalog.

But there are exceptions. For example:

The initials BWV denote numbers that identify J. S. Bach's works. BWV numbers were assigned by cataloger Wolfgang Schmieder in 1950. BWV stands for thematisch-systematisches Verzeichnis der musikalischen Werke von Johann Sebastian Bach (thematic-systematic catalog of musical works of Johann Sebastian Bach), which is the title Schmieder gave to his catalog.

Today, Schmieder's BWV numbers are universally used and accepted as the standard numbering system for Bach's works. For example, Bach's Mass in B minor is assigned the number BWV 232, which may denote Bach's 232nd opus, but not necessarily. Why can't opus numbers be relied on to be identical to catalog numbers? Opus numbers are usually numbered according to the order of publication, but opus numbers can be proven wrong as research uncovers new data about the order of a composer's compositions.

For reasons like these, the BWV catalog is occasionally updated, with newly discovered works added at its end. Schmieder listed works he believed to be incomplete or of doubtful authenticity at the time of cataloging with the notation BWV Anhang (BWV appendix); and he identified these works by the notation BWV Anh. The Composer Catalogs table does not use BWV Anh numbers as symbol notations for Bach's works.

Further, numbers that Schmieder assigned to Bach's works in his older catalogs are sometimes denoted by the letter S, where S stands for Schmieder (for example, S. 232 instead of BWV 232). S numbers are referred to as Schmieder Numbers. Out of modesty, Schmieder opposed this numbering system and the symbols for Bach's works were later changed to BWV numbers. For this reason, the Composer Catalogs table lists both BWV and S as symbol notations for Bach's catalog.



The world of composer catalogs is replete with special cases and exceptions. Keep an eye out for them.

discrepancies and omissions

In most cases, the citations in a given composer catalog are exhaustive; that is, all (or nearly all) the works actually written by a named composer are cited in a catalog for that composer. However, sometimes there are discrepancies: there can be omissions; different catalogs on the same composer sometimes disagree on dates, opus numbers, or other details; catalogers may spell the name of a composer differently; catalogers may disagree on the identity of the composer or the publisher; catalogers may disagree about a work's provenance or attribution. The list of exceptions can go on and on.

The conclusion: Expect discrepancies and omissions when consulting composer catalogs.

  • The cataloger is not usually to blame; it's the nature of the game. See why at the page called More About Classical Music Catalogers And Cataloging—An Appreciation: click here.


errors & omissions

Because of the scope of the composer catalog field, it has not been possible to accomplish the research necessary to confirm the accuracy or currency of every entry in the Table. By no means is the Table a complete list of the catalogs or related literature in the field.

Be alert for possible errors or omissions, especially in the names and titles of composers, catalogers, catalog codes, and catalog titles in the Table or at other web sites cited in the Table.

Works cited in the Table may be out of print; web sites may no longer available. New editions and updates to older catalogs may be available but the latest editions or web sites may not be listed.

multiple catalogs for the same composer

In some cases, more than one cataloger has stepped up to the plate and taken a swing at cataloging the works of a given composer. Scarlatti, Soler, and Vivaldi are examples of composers for whom more than one catalog exists.

There are many reasons why a cataloger may be motivated to assemble a catalog for a composer even though one or more other catalogs are extant:

  • No catalog is final. New works or revisions to old works by a given composer may come to light after earlier catalogs have been published.
  • The accuracy or completeness of a cataloger's information or judgment may be called into question by another cataloger.
  • A cataloger may wish to produce a specialized catalog that focuses on a particular aspect of a composer's work, for example a composer's violin music or symphonic music.
  • New research may bring to light new information that warrants a new catalog.
  • A cataloger who opposes the positions taken by other catalogs may wish to have his voice heard.

A cataloger can usually justify the development of a new catalog by citing these kinds of reasons, and most reasonable observers consider such reasons valid.

But despite differences among multiple catalogers and catalogs, two or more catalogs made for a given composer's works normally will agree on most (or even on all) counts. In cases where catalogs of the same composer differ with one another, a catalog user should look for and take note of the differences among multiple catalogs as well as of their equivalents.

In some cases, it is possible to locate a published cross reference that cites multiple catalogs for the works of a single composer and that equates individual entries in the multiple catalogs with each other. Such cross references, known as concordances, can be useful tools because they identify which multiple catalogs are extant for a given composer. theyalso may help a reader identify and compare the citation for a given work as listed in one catalog with the citations in the other catalogs for the same work. For example:

  • The Classical Netweb site offers a concordance (cross reference) of the instrumental works of Vivaldi as cited by four different catalogers, giving a different catalog number for each specific work. The catalog number it supplies for each work in each catalog is the one that the cataloger assigned. It also provides instrumentation and cataloger comments for each work and catalog manuscript sources for each work sorted by Ryom number.
  • The Chateau Gris web site offers a concordance of Soler Editions that cross-references all editions of Soler's harpsichord sonatas.
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