Peter Allen Greenbaum was born on Oct. 29, 1946, in London. The gift of a cheap guitar put the 10-year-old Green on a musical path.

He was barely out of his teens when he got his first big break in 1966, replacing Eric Clapton in John Mayall’s Bluesbreakers — initially for just a week in 1965 after Clapton abruptly took off for a Greek holiday. Clapton quit for good soon after and Green was in.

In the Bluesbreakers he was reunited with Mick Fleetwood, a former colleague in Peter B’s Looners. Mayall added bass player McVie soon after.

The three departed the next year, forming the core of the band initially billed as “Peter Green’s Fleetwood Mac featuring (guitarist) Jeremy Spencer.”

Fleetwood Mac made its debut at the British Blues and Jazz festival in the summer of 1967, which led to a recording contract, then an eponymous first album in February 1968. The album, which included “Long Grey Mare” and three other songs by Green, stayed on the British charts for 13 months.

The band’s early albums were heavy blues-rock affairs marked by Green’s fluid, evocative guitar style and gravelly vocals. Notable singles included “Oh Well” and the Latin-flavored “Black Magic Woman,” later a hit for Carlos Santana.

But as the band flourished, Green became increasingly erratic, even paranoid. Drugs played a part in his unraveling.