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
Austrian National Library also successfully introduced the card index. This facilitated the continuous updating of the inventory. After the Holy Roman Empire was dissolved by Napoleon and the Austrian Empire proclaimed in its place, the library was again reorganized. Under custodian Paul Strattmann, the library received a program for the first time which described its order; the library gained a three-way viewpoint: The collection politics of the Imperial Library separated at the beginning the 19th century appreciably due to the requirements of the representation and its attention to scientific works. The multinational condition of the Austrian Empire brought with itself that, not only