That's true, but it's not the whole story. Peter Green formed the band with John McVie (the first dates actually featured Bob Brunning) and Mick Fleetwood. Jeremy Spencer and Danny Kirwan followed them into the line up. Apart from giving them most of their distinctive guitar sound, Peter Green wrote most of the early hits. The one exception was Little Willie John's "Need Your Love So Bad". Within the space of about three years, all three guitarists started behaving very oddly and then left. (Drink, drugs and religion are the rumoured culprits).
For a time, the Californinan songwriter Bob Welch was in the band. There were also one or two fake line ups, put together by agents and managers who claimed they had the rights to the band name.
The modern Fleetwood Mac is, as Poppogator says, essentially a Californian pop group with the rhythm section of the original blues band.