Köchel catalogue Köchel catalogue The Köchel catalogue () is a chronological catalogue of compositions by Wolfgang Amadeus Mozart, originally created by Ludwig von Köchel, in which the entries are abbreviated "K." and "KV". The numbers of the Köchel catalogue reflect the continuing establishment of a complete chronology of Mozart's works, and provide a shorthand reference to the compositions. According to Köchel's counting, "Requiem in D minor" is the 626th piece Mozart composed, thus is designated either "K. 626" or "KV 626"; however, his original catalogue (1862) of Mozart has been twice revised, and some works have had three KV. numbers, e.g. Mozart's
19th-century philosophy Stuart Mill promoted the idea that actions are right as they maximize happiness, and happiness alone. Developed by Karl Marx and Friedrich Engels in the mid-to-late-19th Century, Marxism is a sociopolitical and economic view based on the philosophy of dialectical materialism, which opposes idealism in favour of the materialist viewpoint. Marx analysed history itself as the progression of dialectics in the form of class struggle. From this it is argued that "the history of all hitherto existing society is the history of class struggles." According to Marx, this began with the phase of primitive communism (hunter-gatherer society), after which the