Legendary singer-songwriter David Crosby died earlier this week on Wednesday, January 18, and Neil Young has paid tribute to the musician. Young took to his website, posting a statement mourning the loss of his friend, whom he called “the soul of CSNY.”

“David is gone, but his music lives on,” wrote Young. “The soul of CSNY, David’s voice and energy were at the heart of our band. His great songs stood for what we believed in and it was always fun and exciting when we got to play together.”

In 1969, Crosby teamed up with Stephen Stills and Graham Nash to form Crosby, Stills, & Nash, which later became Crosby, Stills, Nash, & Young, or CSNY, when Young joined the trio in 1970. The group released many works together, their last being 1999’s Looking Forward.

Over the years, Crosby and Young had a complicated relationship. Crosby’s substance abuse issues contributed to an ongoing climate of hostility and competition within the band, even causing the bandmates to refuse to speak to one another at times. During an interview on The Howard Stern Show in 2014, Young said: “I wish [Crosby] the best with his life. There’s love there. There’s just nothing else there.”

Stills and Nash also issued statements when Crosby passed. Stills wrote recalled that Crosby was “the glue that held us together as our vocals soared.” Nash took to Instagram, commemorating “the deep friendship [they] shared over all these many long years.” (Pitchfork)