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
Christianity in the 19th century thoroughly protean. The word "liberal" in liberal Christianity does not refer to a leftist political agenda but rather to insights developed during the Age of Enlightenment. Generally speaking, Enlightenment-era liberalism held that people are political creatures and that liberty of thought and expression should be their highest value. The development of liberal Christianity owes a lot to the works of theologian Friedrich Schleiermacher. As a whole, liberal Christianity is a product of a continuing philosophical dialogue. Historian Kenneth Scott Latourette argues that the outlook for Protestantism at the start of the 19th century was discouraging. It was a regional religion