Which jazz musician is known for pioneering free jazz?

Ornette Coleman is recognized as a pivotal figure in the development of free jazz, a genre characterized by its departure from traditional harmonic structures and improvisational constraints. In the late 1950s, Coleman introduced a new approach to music that emphasized collective improvisation and a focus on individual expression, allowing musicians to explore unconventional melodies and rhythms without relying on predetermined chord changes.

His seminal album, "The Shape of Jazz to Come," released in 1959, is often cited as a landmark recording in the free jazz movement. It showcased his innovative use of "harmolodics," a concept he formulated that sought to equalize the roles of harmony, melody, and rhythm, thereby allowing performers greater freedom in their improvisations.

While other musicians, such as John Coltrane, Thelonious Monk, and Bill Evans, contributed significantly to different styles and developments within jazz, it was Coleman's radical approach that truly established the foundation for free jazz as a distinct genre.