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 history of the Catholic Church in the United States 19th-century history of the Catholic Church in the United States The 19th-century history of the Catholic Church in the United States was characterized by several unsuccessful attempts by Catholics to culturally integrate themselves into the mainstream American culture of that century. Only during the 20th century did this fully succeed, with the election of John F. Kennedy to the presidency in 1960. During the 19th century, a wave of immigrants from Ireland, Germany, Italy, Eastern Europe and elsewhere swelled the number of Roman Catholics. Substantial numbers of Catholics also came from French Canada during the mid-19th century and settled in