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
19th-century Catholic periodical literature New York City, Detroit, Philadelphia, Winona, Cleveland, Ohio, Toledo, Baltimore, Pittsburgh, Stevens Point, Manitowoc, Mahanoy City, and Wilkes-Barre. Brazil also had a Polish publication. 19th-century Catholic periodical literature The 19th-century Catholic periodical literature is unique in many respects. Most of the periodical publications in mainly Catholic countries can be regarded as "Catholic" literature up to a few decades before 1800: the editorial line is implicitly Catholic in most instances. The development of the press in the 19th century was in general terms a major factor in secularization according to Owen Chadwick. On the other hand, mass printing also meant that