Contrafact

A contrafact is a musical work based on a prior work. The term comes from classical music and has only since the 1970s been applied to jazz, where it is still not standard. In classical music, contrafacts have been used as early as the parody mass and In Nomine of the 16th century. More recently, Cheap Imitation (1969) by John Cage was produced by systematically changing notes from the melody line of Socrate by Erik Satie using chance procedures.