Chronologic-thematic Directory of all compositions of Wolfgang Amadeus Mozart

Catalog by Ritter von Ludwig Koechel, 1800-1877

Ludwig Ritter von Koechel published his famous catalog of Mozart's compositions in 1862. His concept, to number the works in chronological order, was simple in theory. But it was bound to cause headaches for those who followed.

Chronological order:
1761 to 1765: K. 1a to K. 23
1766 to 1770: K. 24 to K. 74a
1771 to 1775: K. 74b to K. 219
1776 to 1780: K. 238 to K. 365a
1781 to 1785: K. 366 to K. 484e
1786 to 1791: K. 485 to K. 626b

Since the first edition, there have been five revisions of Koechel's work. Only two are significant: the third edition, revised by Alfred Einstein in 1936; and the sixth, edited in 1964 by Franz Giegling, Alexander Weinmann and Gerd Sievers. The latter, especially, incorporates many newly discovered works and revises the dates assigned to many of the compositions.

In updating the catalog, the quandary editors faced was that Koechel's first-edition numbers had become integrated into virtually every document related to Mozart, including books, scores, concert programs and recordings. So even though modern scholarship could correct the dates of many compositions, tradition would not allow the catalog numbers to be simply rearranged.

The problem was "solved" by appending lowercase (and, later, uppercase) letters to the original numbers. This allowed new designations to be inserted between older ones. For example, Mozart's Missa solemnis in C minor, "Waisenhausmesse", originally designated K. 139, became K. 114a (between K. 114 and K. 115) in Einstein's edition, and K. 47a (between K. 47 and K. 48) in the sixth.

This solution works, but it can be confusing. After all, it's much simpler to refer to Mozart's "Little" G Minor Symphony as K. 183 (first-edition) than as K. 173dB (sixth edition). Because of this, many modern publications have adopted a compromise, following Koechel's original scheme whenever possible and using later designations only for works discovered (or reconstructed) after 1862.

For the sake of consistency (and out of respect for recent scholarship), the Mozart Project avoids that convention and uses the sixth edition numbers for all of Mozart's compositions; when they are used, Koechel's first-edition designations are given in parentheses.

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