The family put out a statement that said ... "It is with great sadness that the family of Peter Green announce his death this weekend, peacefully in his sleep."

Green, a blues/rock guitarist, created Fleetwood Mac with Mick Fleetwood way back in '67, and the group produced an insane number of hits ... the insanity only surpassed by the drama inside the group.

Among the hits ... "Black Magic Woman" and "Need Your Love So Bad."

The group was originally known as Peter Green's Fleetwood Mac featuring Jeremy Spencer. It's a mouthful, and was collapsed to simply Fleetwood Mac several years later.

Peter left the group in 1970, creating a guitarist void in the group that was eventually filled by Lindsey Buckingham. He struggled with mental illness, which was a principal reason he left the group.

There were 9 members of the band during the years -- Mick, Peter, Stevie Nicks, Lindsey Buckingham, John McVie, Christine McVie, Danny Kirwan, Bob Welch and Jeremy Spencer. All but Welch were inducted into the Rock & Roll Hall of Fame in 1998.