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
Schubert Thematic Catalogue the 1951 edition, with updates derived from scholarship that had been published since 1951. From 1983 compact versions of the catalogue appeared, edited by Werner Aderhold and others. Changes to the numbering of Schubert's works were minor in these later editions. Schubert Thematic Catalogue Schubert: Thematic Catalogue of all his Works in Chronological Order, also known as the Deutsch catalogue, is a numbered list of all compositions by Franz Schubert compiled by Otto Erich Deutsch. Since its first publication in 1951, Deutsch (abbreviated as D or D.) numbers are used for the unique identification of Schubert's compositions. The Deutsch catalogue