Chris Squire, the bass and heart of Yes, one of the world's most influential progressive rock bands, has died. He was 67.

“It’s with the heaviest of hearts and unbearable sadness that we must inform you of the passing of our dear friend,” reads a post published on Yes' Facebook page. According to the post, the British bassist died in his sleep at home in Phoenix, Arizona, less than six weeks after announcing he'd be taking a break from touring to undergo treatment for acute erythroid leukemia.

After playing in a number of small bands, Squire met Yes’ co-founders, Jon Anderson and Peter Banks, in 1968 and since then, Yes has been working more or less constantly. Yes released 21 studio albums and played some of the largest music venues in the world, including Madison Square Garden, Royal Albert Hall and Wembley Stadium, and thanks to multiple generations of fans, the band's biggest successes were spread across decades; its best-selling album, 1983's "90215," went triple platinum more than a decade after the band's previous best-seller, "Fragile," came out in 1971. “90215” was driven by the success of “Owner of a Lonely Heart,” a song that continues to feature in film and television soundtracks.

While the band is not in the Rock and Roll Hall of Fame, its absence is an ongoing source of controversy about which Dr. Lauren Onkey, the museum’s vice president of education and public programs, felt compelled to write an open letter explanation. The band's often ostentatious style, which alienated some, was intended to be a platform that would showcase the talents of its individual members. And while many musicians came and went through the band’s tenure, the platform certainly worked for Squire. In 2014, readers of NME named him of the 40 greatest bass players of all time.