Rhodri Marsden's Interesting Objects: Kool Herc's party flyer

* The flyer is 41 years old, tatty and scrawled in biro on the back of an index card. It's for a "Back To School Jam" in the recreation room of 1520 Sedgwick Avenue, a high-rise block in New York's Bronx district, with admission a very reasonable 25 cents for women and 50 cents for men. At a glance it looks like a pretty nondescript event, but that night is deemed by many to have seen the birth of hip-hop.

* Cindy Campbell threw the party. Her brother, Clive, known as Kool Herc, was DJing. Other "special guests" are listed on the flyer as Coco, Klark K and Timmy T, but rather like the Sex Pistols' famous gig at London's 100 Club, the list of people who were there (or later claimed to be) is long and illustrious, including names such as Afrika Bambaataa, Grandmaster Flash and KRS-One.

* Kool Herc had been working on a technique where he used two copies of a record to keep a song's drum break going on for longer than the usual four or eight bars, switching back and forth between decks. He unveiled it at that party. His friend Coke La Rock picked up the microphone, calling out names and improvising lines in an attempt to impress the girls in attendance. It was a hip-hop blueprint.

* In reality, a cultural force like hip-hop with its graffiti, beats, breakdancing and rapping could never have sprung from a single event, but Cindy C's party, intended to fund a shopping trip, certainly helped to give impetus to a movement. When 1520 Sedgwick was threatened with purchase by a private equity firm in 2010, Kool Herc described the building as "a piece of the American Dream". Cindy's flyer is now held in an archive at the African American studies department of Harvard University.

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