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 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