Peter Tork, a member of the massively popular ’60s band the Monkees, has died. The Washington Post reports that Anne Thorkelson, Tork’s sister, has confirmed news of Tork’s death, though she declined to say how he died. Tork was 77.

Tork, born Peter Thorkelson, was born in Washington, DC, and he grew up largely in Connecticut. After college, he moved to New York and joined the thriving Greenwich Village folk scene. Tork auditioned for The Monkees, a sitcom about a band of four up-and-coming musicians, after his friend Stephen Stills suggested him for the job. Tork, the oldest member of the group, became the bassist.

The Monkees were an instant pop phenomenon. The band members generally didn’t play on their records, with session musicians playing their parts instead. But Tork, who played a number of instruments, was occasionally allowed to play some of those instruments on the records. He was, for instance, responsible for the piano intro of the #1 hit “Daydream Believer.” (He also played banjo on George Harrison’s score for the 1968 movie Wonderwall.) On the TV show, Tork played a sort of clueless ditz, and his bumbling was one of the major sources of comedy.

The Monkees eventually wrestled creative control away from their management, and they kept on as a band after their TV show was cancelled, making strange time-capsule artifacts like the psychedelic 1968 movie Head. But an exhausted Tork left the Monkees at the end of 1968. After leaving the Monkees, Tork struggled creatively and eventually left the music and TV businesses. He served a few months in prison for hashish possession, and he briefly became a high school teacher in Southern California.

Tork reunited with the Monkees in 1986, and he continued to tour and perform with them until his death. (The Monkees released the holiday album Christmas Party just last year.) Tork also released the solo album Stranger Things Have Happened in 1994, and he played the recurring role of Topanga’s father on the sitcom Boy Meets World. He was diagnosed with adenoid cystic carcinoma in 2009, but the cancer was treated, and it’s not yet known whether that contributed to his death. Tork is the second of the four Monkees to pass away; singer Davy Jones died of a heart attack in 2012, at the age of 66.

Below, watch a few Monkees videos: