In 1950 a musicologist named Wolfgang Schmieder published an enormous catalogue of J.S. Bach’s works, but Schmieder organized it by category, that is, by type of composition, not by date of composition. The catalogue is known in German as the Bach-Werke-Verzeichnis, or BWV, and that’s why you often see Bach’s works listed in programs with their BWV numbers.
Mozart’s works have “K” numbers, for Ludwig Köchel, who published a chronological Mozart catalogue in 1862, and Schubert’s compositions are often given “D” numbers, for the chronological catalogue first published in 1951 by the Viennese scholar Otto Erich Deutsch. And if you’re wondering why there’s no special letter for Beethoven, it’s because Beethoven, pioneer in this area as in so many others, was the first major composer who systematically assigned opus numbers to his own works.
This has been A Minute with Miles – a production of South Carolina Public Radio, made possible by the J.M. Smith Corporation.