I want to take this moment to talk about John Mayall. In my mind, he was one of the originators of blues rock. His band The Bluesbreakers had Eric Clapton, Mick Taylor, and Peter Green as members before 1970. Of course Clapton formed Cream upon leaving, Green formed Fleetwood Mac, and Mick Taylor joined the Stones for what I consider to be their best era. Mayall was there from the beginning, reworking blues classics that spearheaded the British blues movement. Apart from Clapton, Jeff Beck, and Jimmy Page coming from the Yardbirds (Zep was originally called the New Yardbirds), I feel Mayall was the start of it all. The main recording by him that was the blueprint for just about every blues rock band is John Mayall's Bluesbreakers with Eric Clapton, an absolutely essential recording and EC is on fire on it.