After the Beatles' Sgt. Pepper in 1967, many rock musicians began to think that rock should aspire to grand, conceptual song cycles instead of mere "songs." The Who's Tommy (1969) -- the saga of the deaf, dumb, and blind "Pinball Wizard" masterminded by Pete Townsend -- defines the genre. Rock Opera met the Jesus Freak movement in Jesus Christ Superstar in 1971. The Who followed Tommy with Quadrophenia in 1973. In the '90s, Tommy migrated to Broadway and became a national touring show, proving to some that the whole thing was more akin to West Side Story than rock 'n' roll from the start. Rock Operas vary in style and tone, but often merge traditional pop elements -- choirs, strings, classic pop song forms -- with rock 'n' roll.