Michael Lang, a co-creator of a world-renowned musical festival, died on Saturday.

Lang, one of the co-creators and promoters of the 1969 Woodstock musical festival, died at the New York Memorial Sloan Kettering Cancer Center. He had been battling non-Hodgkin’s lymphoma, a type of cancer that starts out in your lymphatic system, affects white blood cell growth, and can result in tumors, according to the Mayo Clinic.