Ludwig Ritter von Köchel since undergone revisions. Mozart's works are often referred to by their K-numbers ("cf." opus number); for example, the "Jupiter" symphony, "Symphony No. 41" K. 551. Moreover, Köchel arranged Mozart's works into twenty-four categories, which were used by Breitkopf & Härtel when they published the first complete edition of Mozart's works from 1877 to 1910, a venture partly funded by Köchel. He also catalogued the works of Johann Fux. Ludwig Ritter von Köchel Ludwig Alois Friedrich Ritter von Köchel (; 14 January 1800 – 3 June 1877) was an Austrian musicologist, writer, composer, botanist and publisher. He is best known for
Köchel catalogue and Georges de St. Foix) reassigned a number of works from the original K appendices into the main catalogue by interpolating new numbers into the main sequence with a lower-case letter suffix. In K some of these were reassessed in the light of scholarship since 1937 and returned to the re-worked appendices: For example, the Divertimento for Wind Octet in E♭ was numbered Anh. 226 in K; Einstein placed it in the K main catalogue as K. 196e, between K. 196 and K. 197; K reassigned it again to the 'doubtful' appendix C as Anh. C 17.01. Some works in