John Tout, the keyboardist whose playing added a crucial component to Renaissance's sound during the band's most creatively fertile and commercially successful period, has passed away.

The group shared the news on its official Facebook page, posting a message that reads in part, "He was an amazing musician, highly contributing to the unique sound of the band from 1970-1980. He was the quiet (but funny) one in the band, always very caring towards the fans and [a] good friend."

Tout, whose age was not mentioned in the post, died of lung failure on May 1, while he was in the care of doctors at the Royal Free Hospital in London.

When Tout joined, Renaissance were in a state of extreme flux; the band had undergone a complete overhaul from its beginnings as project founded by Yardbirds members Keith Relf and Jim McCarty, and by the end of 1970, no original members remained. But manager Miles Copeland heard potential in the group's new sound, and shepherded them through a revamped (but still constantly shifting) lineup that led to a series of increasingly successful albums throughout the '70s.

"I just played what came naturally, really," Tout later said of the way his distinctive playing enhanced Renaissance's classically inspired sound. "It didn't seem as though it was different to me. I just liked classical music, and the idea of Renaissance originally was to feature so-called classical music and that appealed to me, which is why I joined in the first place. ... It was something I enjoyed, playing classical music. It's funny, really, because I like soul music and I was playing soul music for a long time. I suppose the opportunity to do something a bit different came and I took it and carried on."

Tout left the band in 1980, later explaining that at the time, he was subconsciously "blocking off everything to do with music" because of grief over his sister's passing. "I thought the music had to die as well," he recalled. "I just shut myself away. I didn't do anything at all. ... For 10 years, I didn't do anything at all."

Renaissance folded in 1987, but reunited in 1998 with a lineup that boasted a quartet of returning alumni that included Tout, and although he left the following year, he remained part of the band's circle, joining members sporadically in the studio and onstage. He'd planned to work on a new project with former Renaissance bassist Jon Camp, but declining health, including a heart attack he suffered in 2009, prevented involvement.

"He will always be in our hearts and music," concludes the band's Facebook post. "Please share your thoughts and photos of John."

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