Free jazz is a movement of jazz music first developed in the 1950s and 1960s.
Though the music produced by free jazz pioneers varied widely, the common feature was a dissatisfaction with the limitations of bebop, hard bop, and modal jazz, which had developed in the 1940s and '50s. Each in his or her own way, free jazz musicians attempted to alter, extend, or break down the conventions of jazz, often by discarding hitherto invariable features of jazz, such as fixed chord changes or tempos. While usually considered experimental and avant-garde, it has also oppositely been conceived as an attempt to return jazz to its "primitive," often religious roots.
Free jazz is most strongly associated with the '50s innovations of Ornette Coleman and Cecil Taylor and the later works of saxophonist John Coltrane. Other important pioneers included Eric Dolphy, Albert Ayler, Archie Shepp, Bill Dixon, and Sun Ra.
Although today "free jazz" is the generally-used term, many other terms were used to describe the loosely-defined movement, including "avant-garde", "energy music" and "The New Thing" . Free-jazz players were often said to be playing "outside" or "out" (as opposed to "inside", that is, conventionally). .