Greg Lake, co-founder of two prog rock giants — King Crimson and Emerson, Lake & Palmer — died yesterday after a lengthy battle with cancer, according to his manager. He was 69.

Lake’s manager Stewart Young posted to Lake’s official Facebook page today that the musician passed away on December 7, 2016 after “a long and stubborn battle with cancer.” The news comes just nine months after the death of Lake’s former ELP bandmate Keith Emerson.

Chris Squire, the bassist and co-founder of prog-rock giants Yes, died today in Phoenix, Arizona, after battling a rare form of leukemia, according a post on the band’s official Facebook page. He was 67.

Born in Kingsbury, England, on March 4, 1948, Squire was suffering from acute erythroid leukemia. Last month, Yes revealed Squire’s diagnosis, adding that he would have to take a break from touring with the group and that former member Billy Sherwood (with whom Squire had recorded and performed) was stepping in for their co-headlining 2015 North American tour with Toto. This was to be the first time Squire would not be a part of the Yes live line-up.