or bop
In the mid-1940s, a group of musicians, including Dizzy Gillespie , Thelonious Monk , and Charlie Parker , rejected the conventions of {{link=swing">swing to pioneer a self-consciously artistic extension of improvised jazz, which set new technical standards of velocity and harmonic subtlety. Two genres grew out of bebop in the 1950s: the delicate, dry, understated approach that came to be known as cool jazz, and the aggressive, blues -tinged earthiness of hard bop.