Opus number developed other catalogue-number systems; among them the "Bach-Werke-Verzeichnis" (BWV-number), and the "Köchel-Verzeichnis" (K- and KV -numbers) with which are organised the works of Johann Sebastian Bach and Wolfgang Amadeus Mozart, respectively. In the classical period, the Latin word "opus" ("work", "labour") was used to identify, list, and catalogue a work of art. By the 15th and 16th centuries, the word "opus" was used by Italian composers to denote a specific musical composition, and by German composers for collections of music. In compositional practise, numbering musical works in chronological order dates from 17th century Italy, especially Venice. In common usage, the
Catalogues of Beethoven compositions catalogue in the 1950s, in which he included pieces not included in the 19th century complete edition published by Breitkopf and Härtel. Hess included many more fragmentary works than did Kinsky, and his catalog runs to 335 entries in the "Hauptkatalog" (main catalogue), and 66 "doubtful and falsely-attributed" works in an appendix. Many pieces have both WoO and H numbers. Beethoven's compositions are also organized through the Biamonti Catalogue, compiled by Giovanni Biamonti and published in 1968. This work is an attempt to chronologically order all of Beethoven's creative output, in a manner similar to the catalogue of Franz Schubert's