Michael Lang, co-creator of the Woodstock Music & Art Fair, died on Saturday at the age of 77.

Lang died at Memorial Sloan Kettering Cancer Center in New York City. According to family spokesperson Michael Pagnotta, the cause of death was a rare form of non-Hodgkin's lymphoma.

Lang, along with partners Artie Kornfeld, Joel Rosenman and John P. Roberts, planned the famous 1969 festival on Max Yasgur's sprawling dairy farm in Bethel, N.Y. For four days, more than 400,000 attendees were treated to performances by artists including the Grateful Dead, Janis Joplin, Jefferson Airplane, Jimi Hendrix and The Who.

Battling weather issues, late venue changes, and far more attendees than anticipated, Woodstock's free-wheeling ethos of "peace and music" endured, making the festival a defining moment in the decade's countercultural movement.

"Woodstock was a test of whether people of our generation really believed in one another and the world we were struggling to create," Lang wrote in his 2009 book The Road to Woodstock. "How would we do when we were in charge? Could we live as the peaceful community we envisioned? I'd hoped we could."

Born in Brooklyn, NY, Lang briefly attended New York University before moving to Florida. It was there he got the idea for Woodstock after organizing the Miami Pop Festival in 1968, featuring Jimi Hendrix as the headliner.

"I was amazed at the effect music had on the kids," he told Billboard in 2009. "I went from John Lee Hooker to Jimi Hendrix, and they loved it all... and looking at their faces and the way music sort of transformed them really started me in that direction."

Featured prominently in the Academy Award-winning 1970 documentary Woodstock, often riding across the stage grounds on his motorcycle, Lang became one of the more recognizable faces behind the festival.

In later years, he would continue to produce events building on the legacy of that original Woodstock, including festivals Woodstock '94 and Woodstock '99. The latter event, a three-day concert in Rome, N.Y., was infamously plagued by widely-covered acts of violence and reported sexual assault.

In 2019 Lang was planning to stage Woodstock 50, a reimagining of the festival featuring a wide range of performers including Chance the Rapper and Carlos Santana, but the festival was canceled after financial setbacks.

In addition to his wife Tamara, Lang is survived by sons Harry and Laszlo and daughters LariAnn, Shala and Molly.

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