Progressive rock began in 1969 with King Crimson's album "In the Court of the Crimson King" and attempted to extend the boundaries of rock music through complex arrangements, virtuosic musicianship, innovative technology, and influences from genres like classical, jazz, and psychedelia. Key pioneering prog bands of the 1970s included King Crimson, Genesis, Emerson Lake & Palmer, and Rush. While prog waned in popularity in the late 1970s, it maintained a cult following and saw a resurgence in the 1980s with bands like Marillion gaining mainstream success. Prog continues today with classic bands, new acts, and the use of modern technology.