Peter Tork of the Monkees died on Feb. 21, his sister confirmed. He was 77.

Born Peter Halsten Thorkelson in Washington, D.C., he was diagnosed with a rare cancer of the salivary glands in 2009. As he continued battling the disease, Tork missed the last Monkees-related tour dates, which were headed up by Micky Dolenz and Michael Nesmith. Their other original bandmate Davy Jones died in 2012.

"There are no words right now," Dolenz said on Facebook, adding that he's "heartbroken over the loss of my Monkee brother, Peter Tork." Meanwhile, Nesmith said he was told Tork "slipped away peacefully. Yet, as I write this my tears are awash, and my heart is broken. Even though I am clinging to the idea that we all continue, the pain that attends these passings has no cure. It's going to be a rough day."

His family released the following statement:

We are all saddened to share the news that Peter Thorkelson – friend, father, husband, grandfather, philosopher, goofball, entertainer – died peacefully this morning at a family home in Connecticut. Peter succumbed to a 10 year bout with adenoid cystic carcinoma, a rare cancer of the salivary glands. Peter’s energy, intelligence, silliness, and curiosity were traits that for decades brought laughter and enjoyment to millions, including those of us closest to him. Those traits also equipped him well to take on cancer, a condition he met with unwavering humor and courage. We are asking fans who would like to make contributions in Peter’s name to donate to the scholarship fund at The Institute for The Musical Arts in Massachusetts, a nonprofit that provides young women with music education, music recording, and music community. More info can be found here: http://www.ima.org/help-out/in-the-name-of-our-mothers/

Long before joining the made-for-TV Monkees, Tork had been a roots musician in Greenwich Village – and he fashioned his goofball part on their hit television show after a persona from those days. He only occasionally sang lead – notable instances included "Your Auntie Grizelda" – but co-wrote many more tracks, and contributed bass and keyboards to their latter-day sessions.

Stephen Stills, one of Tork's earlier collaborators, actually auditioned for The Monkees TV program first. When Stills was passed over, he suggested Tork give it a shot. Tork assumed, however, that the group would play its own instruments from the beginning. Instead, music producer Don Kirshner used sessions aces to help the Monkees notch their first chart successes.

Arriving after the height of Beatlemania, and assembled together by studio execs, the Monkees were soon derisively dubbed the "prefab four." Tork, who had studied French horn at Minnesota's Carleton College, was "mortified," he told CBS News.

"They were doing [the Monkees' chart-topping debut single 'Last Train to] Clarksville,’ and I wrote a counterpoint," he added. "And I brought it to them, and they said, 'No, no, Peter, you don't understand. This is the record. It's all done. We don't need you.'"

The Monkees got on a commercial roll anyway. Jimi Hendrix served as their support act at one point. But it took two albums for the Monkees to convince the label to let them have more input. They wrote and performed most of 1967's Headquarters and Pisces, Aquarius, Capricorn & Jones Ltd – and ended up outselling both the Beatles and the Rolling Stones that year.

Tork once humbly pointed out that Sgt. Pepper's Lonely Hearts Club Band and Their Satanic Majesties Request were old news by the time Headquarters gained its widest popularity – but "hey," he told Cleveland Scene in 2017, "it's still a hell of a thing."

Unfortunately, their Emmy-winning television show was beginning to run out of steam. The Monkees went off the air in early 1968, though it remained a cult favorite. Tork continued to chafe at their novelty-band status and soon left.

Head, released at the end of 1968, was the last Monkees album to feature Tork until 1987's Pool It!. All four members wouldn't appear together on an album again until 1996's Justus. In the meantime, Tork struggled to find his footing.

He performed with Release, but the band went nowhere, then later worked as a high-school teacher, and reportedly even as a singing waiter. In 1972, he ended up in jail on a petty drug charge, and he struggled with alcohol into the early '80s. Then The Monkees returned to cable television, leading to a celebrated reunion with Dolenz and Jones.

Listen to the Monkees' 'Your Auntie Grizelda'

They continued touring until early in the new millennium, even as Tork came to terms with the Monkees' complicated legacy. “This is not a band, it's an entertainment operation whose function is Monkee music," Tork told the London Telegraph in 2016. "It took me a while to get to grips with that, but what great music it turned out to be! And what a wild and wonderful trip it has taken us on!"

As interest in the Monkees rekindled, Tork finally gained wider individual notice. He appeared on TV shows including Boy Meets World, 7th Heaven, Wings and The King of Queens; released the 1994 solo album Stranger Things Have Happened; worked with folksinger James Lee Stanley; and performed with bands called the Peter Tork Project and Shoe Suede Blues. Onstage, he often reworked Monkees songs, to fans' delight.

Tork later described a scary procedure that accompanied his adenoid cystic carcinoma diagnosis. "I went under the knife in New York at Sloan-Kettering," he told Rolling Stone in 2011. "They sliced open my lip, broke my jaw, reached down inside and carved this thing off my tongue. Later I underwent radiation. My checkups have been clear ever since. I'm excruciatingly lucky. I count my blessings every day."

Interest in his old band remained high. Tork, Dolenz and Jones reunited in 2011, then he was joined by Dolenz and Nesmith for Monkees tours from 2012-14. The band's most recent original studio release, 2016's Good Times!, became a Top 15 hit.

"I refute any claims that any four guys could've done what we did," Tork told Guitar World in 2013. "There was a magic to that collection. We couldn't have chosen each other. It wouldn't have flown. But under the circumstances, they got the right guys."