Greg Lake — the British musician who stood as one of the leading lights of the progressive rock movement and who played key roles in the bands King Crimson and Emerson Lake & Palmer — has died. As the BBC reports, Lake’s manager Stewart Young broke the news on Facebook, writing that Lake died yesterday after “a long and stubborn battle with cancer.” His death comes just nine months after that of his ELP bandmate Keith Emerson, who committed suicide earlier this year. Lake was 69.

Lake helped form the Dorset-based prog band King Crimson in 1968 with his school friend Robert Fripp. Lake sang and played bass in the band, and he also served as a producer on their classic 1969 debut In The Court Of The Crimson King. After about a year, though, Lake left the band and formed ELP with two other members of big prog-rock bands. (He’d still sing on the next King Crimson album and perform with them on Top Of the Pops afterward.)

With ELP, Lake helped pioneer a show-offy, musicianly, classical-influenced form of rock music, though he reportedly pushed the band in a more straightforwardly rocking direction, clashing with Emerson. The band stayed together through to the end of the ’70s and sold tens of millions of records. And in 1975, Lake scored a solo hit of his own with the holiday song “I Believe In Father Christmas.”

After ELP’s breakup, Lake spent a bit of time as a member of the band Asia and played with his own Greg Lake Band. He also reunited with ELP in the ’90s and then again in 2010.

Below, watch some videos of Lake at work.