in the 1950s, recording companies took blues-influenced rock and roll (for example chuck berry and bo diddley) and rockabilly (for example carl perkins and buddy holly) and promoted them as pop music. in the late 1960s and early 1970s, record companies took folk music bands and musicians and helped them to create a new type of music called folk rock or acid rock. folk rock and acid rock mixed folk music, blues and rock and roll (for example the byrds and janis joplin). in the 1970s, record companies created several harder, louder type of blues called blues rock or heavy metal, which became a type of pop music (for example the bands led zeppelin and judas priest).