Green's new band, with former Bluesbreaker Mick Fleetwood on drums and Jeremy Spencer on guitar, was initially called "Peter Green's Fleetwood Mac featuring Jeremy Spencer".
Bob Brunning was temporarily employed on bass guitar (Green's first choice, Bluesbreakers' bassist John McVie, was not yet ready to join the band).
Within a month they played at the Windsor National Jazz and Blues Festival in August 1967, and were quickly signed to Mike Vernon's Blue Horizon label.
Their repertoire consisted mainly of blues covers and originals, mostly written by Green, but some were written by slide guitarist Jeremy Spencer.
The band's first single, Spencer's "I Believe My Time Ain't Long" with Green's "Rambling Pony" as a B-side, did not chart but their eponymous debut album made a significant impression, remaining in the British charts for 37 weeks.
By September 1967, John McVie had replaced Brunning.

Although classic blues covers and blues-styled originals remained prominent in the band's repertoire through this period, Green rapidly blossomed as a songwriter and contributed many successful original compositions from 1968 onwards.
The songs chosen for single release showed Green's style gradually moving away from the group's blues roots into new musical territory.
Their second studio album Mr. Wonderful was released in 1968 and continued the formula of the first album.
In the same year they scored a hit with Green's "Black Magic Woman" (later covered by Santana), followed by the guitar instrumental "Albatross" (1969), which reached number one in the British singles charts.
More hits written by Green followed, including "Oh Well", "Man of the World" (both 1969) and the ominous "The Green Manalishi" (1970).
The double album Blues Jam in Chicago (1969) was recorded at the Chess Records Ter-Mar Studio in Chicago.
There, under the joint supervision of Vernon and Marshall Chess, they recorded with some of their American blues heroes including Otis Spann, Big Walter Horton, Willie Dixon, J. T. Brown and Buddy Guy.

In 1969, after signing to Immediate Records for one single ("Man of the World", prior to that label's collapse) the group signed with Warner Bros. Records' Reprise Records label and recorded their third studio album Then Play On, prominently featuring the group's new third guitarist, 18-year-old Danny Kirwan.
Green had first seen Kirwan in 1967 playing with his blues trio Boilerhouse, with Trevor Stevens on bass and Dave Terrey on drums.
Green was impressed with Kirwan's playing and used the band as a support act for Fleetwood Mac before recruiting Kirwan to his own band in 1968 at the suggestion of Mick Fleetwood.

Beginning with "Man of the World"'s melancholy lyric, Green's bandmates began to notice changes in his state of mind.
He was taking large doses of LSD, grew a beard and began to wear robes and a crucifix.
Mick Fleetwood recalls Green becoming concerned about accumulating wealth: "I had conversations with Peter Green around that time and he was obsessive about us not making money, wanting us to give it all away.
And I'd say, 'Well you can do it, I don't wanna do that, and that doesn't make me a bad person.'"

While touring Europe in late March 1970, Green took LSD at a party at a commune in Munich, an incident cited by Fleetwood Mac manager Clifford Davis as the crucial point in his mental decline.
Communard Rainer Langhans mentions in his autobiography that he and Uschi Obermaier met Green in Munich, where they invited him to their Highfisch-Kommune.
Fleetwood Mac roadie Dinky Dawson remembers that Green went to the party with another roadie, Dennis Keane, and that when Keane returned to the band's hotel to explain that Green would not leave the commune, Keane, Dawson and Mick Fleetwood travelled there to fetch him.
By contrast, Green stated that he had fond memories of jamming at the commune when speaking in 2009: "I had a good play there, it was great, someone recorded it, they gave me a tape.
There were people playing along, a few of us just fooling around and it was... yeah it was great."
He told Jeremy Spencer a
Green's new band, with former Bluesbreaker Mick Fleetwood on drums and Jeremy Spencer on guitar, was initially called "Peter Green's Fleetwood Mac featuring Jeremy Spencer". Bob Brunning was temporarily employed on bass guitar (Green's first choice, Bluesbreakers' bassist John McVie, was not yet ready to join the band). Within a month they played at the Windsor National Jazz and Blues Festival in August 1967, and were quickly signed to Mike Vernon's Blue Horizon label. Their repertoire consisted mainly of blues covers and originals, mostly written by Green, but some were written by slide guitarist Jeremy Spencer. The band's first single, Spencer's "I Believe My Time Ain't Long" with Green's "Rambling Pony" as a B-side, did not chart but their eponymous debut album made a significant impression, remaining in the British charts for 37 weeks. By September 1967, John McVie had replaced Brunning.
Although classic blues covers and blues-styled originals remained prominent in the band's repertoire through this period, Green rapidly blossomed as a songwriter and contributed many successful original compositions from 1968 onwards. The songs chosen for single release showed Green's style gradually moving away from the group's blues roots into new musical territory. Their second studio album Mr. Wonderful was released in 1968 and continued the formula of the first album. In the same year they scored a hit with Green's "Black Magic Woman" (later covered by Santana), followed by the guitar instrumental "Albatross" (1969), which reached number one in the British singles charts. More hits written by Green followed, including "Oh Well", "Man of the World" (both 1969) and the ominous "The Green Manalishi" (1970). The double album Blues Jam in Chicago (1969) was recorded at the Chess Records Ter-Mar Studio in Chicago. There, under the joint supervision of Vernon and Marshall Chess, they recorded with some of their American blues heroes including Otis Spann, Big Walter Horton, Willie Dixon, J. T. Brown and Buddy Guy.
In 1969, after signing to Immediate Records for one single ("Man of the World", prior to that label's collapse) the group signed with Warner Bros. Records' Reprise Records label and recorded their third studio album Then Play On, prominently featuring the group's new third guitarist, 18-year-old Danny Kirwan. Green had first seen Kirwan in 1967 playing with his blues trio Boilerhouse, with Trevor Stevens on bass and Dave Terrey on drums. Green was impressed with Kirwan's playing and used the band as a support act for Fleetwood Mac before recruiting Kirwan to his own band in 1968 at the suggestion of Mick Fleetwood.
Beginning with "Man of the World"'s melancholy lyric, Green's bandmates began to notice changes in his state of mind. He was taking large doses of LSD, grew a beard and began to wear robes and a crucifix. Mick Fleetwood recalls Green becoming concerned about accumulating wealth: "I had conversations with Peter Green around that time and he was obsessive about us not making money, wanting us to give it all away. And I'd say, 'Well you can do it, I don't wanna do that, and that doesn't make me a bad person.'"
While touring Europe in late March 1970, Green took LSD at a party at a commune in Munich, an incident cited by Fleetwood Mac manager Clifford Davis as the crucial point in his mental decline. Communard Rainer Langhans mentions in his autobiography that he and Uschi Obermaier met Green in Munich, where they invited him to their Highfisch-Kommune. Fleetwood Mac roadie Dinky Dawson remembers that Green went to the party with another roadie, Dennis Keane, and that when Keane returned to the band's hotel to explain that Green would not leave the commune, Keane, Dawson and Mick Fleetwood travelled there to fetch him. By contrast, Green stated that he had fond memories of jamming at the commune when speaking in 2009: "I had a good play there, it was great, someone recorded it, they gave me a tape. There were people playing along, a few of us just fooling around and it was... yeah it was great." He told Jeremy Spencer a
Peter Green (musician)