Iron Maiden drummer Clive Burr passed away in his sleep on Tuesday at the age of 56.

In a statement release on the band’s website, founder Steve Harris wrote, “This is terribly sad news. Clive was a very old friend of all of us. He was a wonderful person and an amazing drummer who made a valuable contribution to Maiden in the early days when we were starting out.”

Burr was dianosed with primary progressive multiple scleroris in 1994.  He is survived by his partner Mimi.