(By A.D. Carson, assistant professor of hip-hop) Whenever I teach courses on hip-hop at the University of Virginia, I provide a brief overview of where hip-hop music began. One of the important dates I use is Aug. 11, 1973. That’s when DJ Kool Herc, who was 18 at the time, threw a “Back To School Jam” for his sister Cindy in the South Bronx – in the rec room at 1520 Sedgwick Ave., to be specific.