What year was 'Grease' the musical first performed live on stage?

Grease is a 1971 musical by Jim Jacobs and Warren Casey with additional songs written by John Farrar (movie and post revivals). Named after the 1950s United States working-class youth subculture known as greasers, the musical is set in 1959 at fictional Rydell High School (based on William Howard Taft School in Chicago, Illinois and follows ten working-class teenagers as they navigate the complexities of peer pressure, politics, personal core values, and love.

Grease was first performed in 1971 in the original Kingston Mines nightclub in Chicago (since demolished). From there, it has been successful on both stage and screen, but the content has been diluted and its teenage characters have become less Chicago habitués and more generic. At the time that it closed in 1980, Grease's 3,388-performance run was the longest yet in Broadway history, although it was surpassed by A Chorus Line a few years later. It went on to become a West End hit, a successful feature film, two popular Broadway revivals in 1994 and 2007, and a staple of regional theatre, summer stock, community theatre, and high school and middle school drama groups. It remains Broadway's 15th longest-running show.