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
Schubert opus/Deutsch number concordance Schubert opus/Deutsch number concordance Franz Schubert (31 January 1797 – 19 November 1828) was an Austrian composer. This is a concordance of those compositions by Schubert that were given opus numbers, and their corresponding Deutsch catalogue numbers. Only a small minority of Schubert's works were published in his lifetime. Not all published works were allocated opus numbers, and the sequence of opus numbers that were allocated bore little relationship to the order in which the works were either composed or published. For example, the first of his works to be published, the song "Die Forelle", was given the opus number