LIVERMORE, CALIF. • Sonny Barger, the leather-clad fixture of 1960s counterculture and figurehead of the Hells Angels motorcycle club who was at the notorious Rolling Stones concert at Altamont Speedway, has died. He was 83.

Barger’s death was announced on his Facebook page late Wednesday.

“If you are reading this message, you’ll know that I’m gone. I’ve asked that this note be posted immediately after my passing,” a posting said. “I’ve lived a long and good life filled with adventure. And I’ve had the privilege to be part of an amazing club.”

The post said that “I passed peacefully after a brief battle with cancer.”

Barger’s former attorney, Fritz Clapp, said that Barger had liver cancer and died Wednesday night at home in Livermore, Calif. Barger composed the post placed on the Facebook page managed by Barger’s wife, Zorana, he said.

Ralph “Sonny” Barger was a founding member of the Oakland, Calif., chapter of the Hells Angels in 1957 and was present at its most infamous moment — the 1969 Rolling Stones concert at Altamont Speedway during which bikers hired as security staff fatally stabbed a concertgoer who pulled a gun on one of their members.

The Hells Angels were typically depicted by the media as the dark fringe of the 1960s counterculture, embracing freedom, drugs and rock music, but also crime and violence. But Barger downplayed the outlaw reputation. —