Hard Bop is a subgenre of Bop that developed in the mid-1950s following the death of Charlie Parker, largely building upon the legacy of the classic Bop established by Parker and his cohorts in the '40s. But whereas classic Bop built much of its harmonic vocabulary from Pop and showtunes, Hard Bop looked primarily to the blues for its influence. It also incorporated church music, using melodies and call-and-response patterns derived from Gospel. For this reason, some Hard Bop fell under the critics' label "soul jazz." The swing was deeper and less fluid than Bop; some critics even called it "Funk." Hard Bop also incorporated Afro-Cuban styles such as Salsa and Mambo to form its own brand of Latin Jazz rhythm. Overall, it's one of the most brash, raucous forms of modern jazz.