Hip hop’s roots as a musical phenomenon are subject to debate, but its roots as a commercial phenomenon are much clearer. They trace back directly to January 5, 1980, when the song “Rapper’s Delight” became the first hip hop single ever to reach the Billboard top 40.

Prior to the success of “Rapper’s Delight,” hip hop was little known outside of New York City, and little known even within New York City by those whose orbits were limited to Midtown and Downtown Manhattan. The basic elements of hip hop—MCs rapping, DJs mixing and scratching, B-Boys break-dancing—were all in place by 1979, but you could not walk into a record store in Times Square and buy a hip hop album. Hip hop was something you had to experience live, in clubs and at parties in neighborhoods like the South Bronx and Harlem.

Those were the settings in which founding fathers of hip hop like Grandmaster Flash, Kurtis Blow and DJ Kool Herc were busy making their names while the crowds at Studio 54 danced away the last days of the disco just a few miles to the south. Meanwhile, it was a businesswoman from New Jersey who put the two trends together to give birth to an industry. Her name was Sylvia Robinson, formerly a singer and later the owner of a small record label called All Platinum. After hearing a DJ rapping over records in a Harlem club, she set her son Joey to the task of finding someone who could do the same thing on tape. Joey recruited his friend Big Bank Hank from an Englewood, New Jersey, pizzeria, and Master Gee and Wonder Mike from the surrounding neighborhood. This was on a Friday. Sylvia named the newly formed trio after the Sugar Hill section of Harlem, chose Chic’s disco smash “Good Times” as a backing track and scheduled studio time for the following Monday.

What happened between that Friday and Monday is a subject of some controversy. It involves Big Bank Hank borrowing his lyrics almost wholesale from the notebook of Harlem MC Grandmaster Caz, whose name appears nowhere on the credits or royalty checks for “Rapper’s Delight.” What happened on Monday, however, was straightforward and revolutionary: the making of a record that began, “I said a hip, hop, the hippie, the hippie…” and ended up changing the course of music history.