The Newport Jazz Festival had been a summer tradition in Rhode Island for more than a decade, highlighting the best swing, bebop, and big band talents of the day. But in 1969, organizers decided to bring a selection of rock groups onto the lineup, including Led Zeppelin, the Mothers of Invention, and Sly and the Family Stone. Things did not go smoothly. Crowds crashed fences, riots threatened to break out, toilets overflowed. But amid the chaos, some seriously great music was made. Miles Davis tried out his revolutionary electric sound, tearing through a ferocious set that previewed Bitches Brew, the landmark effort the trumpeter recorded just a few weeks later. Zeppelin’s heavy blues-rock fusion gave a glimpse of the stadium-ready sound that would dominate the 1970s. And James Brown’s set caught the Godfather of Soul at a career high point, bringing blindingly brilliant funk to Newport’s Sunday afternoon.