Phil Lesh, bassist for the Grateful Dead, died this morning (October 25), according to a statement on his official social media accounts. A cause of death was not shared, just that he “passed peacefully” and that he “was surrounded by his family and full of love.” Lesh was 84 years old.

Philip Chapman Lesh was born and raised in Berkeley, California. He enrolled at the University of California, Berkeley, in 1961, where he studied music and composition under the Italian composer Luciano Berio. He was also a classmate of Steve Reich at the university.

In 1965, Lesh, a bassist-in-training, joined Jerry Garcia, Bob Weir, Ron “Pigpen” McKernan, and Bill Kreutzmann in a band called the Warlocks. On Saturday, December 4, 1965, they adopted a new name for one of Ken Kesey’s Acid Test parties, in San Jose: They were the Grateful Dead.

Grateful Dead released their first album, also called Grateful Dead, in March 1967, but they were just as well-known across the Bay Area for their long, free-form concerts. More albums followed as the band’s acclaim and notoriety grew. Lesh did not take the lead, as a writer or a singer, on many songs, but he did co-write the opening and closing songs on 1970’s American Beauty, “Box of Rain” and “Truckin’.” He also sang the lead vocals on “Box of Rain.” And, regarding “Truckin’,” Lesh once said, “We took our experiences on the road and made it poetry… the last chorus defines the band itself.”

Lesh was a fixture with the Grateful Dead until the band’s dissolution, in 1995, following the death of Jerry Garcia. He soon began performing with a rotating lineup of members as Phil Lesh and Friends. He did not, however, join his former bandmates in the revival act Dead & Company.

In the mid-2000s, Lesh wrote about his years with the Grateful Dead in the book Searching for the Sound. Around that time, the musician also revealed that he had been diagnosed with prostate cancer, ultimately having surgery to treat it. Nearly a decade later, he had bladder cancer surgery.