Most bands morph into existence, picking-up members over a period of weeks or months. One of Rock's original power trio's was formed in a single day, July 16, 1966.
His time as a member of the Yardbirds and John Mayall's Bluesbreakers made Eric Clapton the best known of the three, but it was Ginger Baker that brought the members of Cream together. Baker had been the drummer in the Graham Bond Organisation, a band that also included Jack Bruce. When Ginger proposed forming a new band with Clapton, Eric agreed to it, provided that Bruce, who had been a member of the Bluesbreakers during EC's stint with Mayall, be included. Since Bruce and Baker had frequently feuded during their time together in the Bond band, Baker was reluctant to go along with it but did because Clapton insisted. Baker and Bruce continued to knock heads during the few years and four albums Cream was together.
In 1969, weary of the ongoing battles between Baker and Bruce, Clapton and Baker joined former Spencer Davis Group and Traffic member Steve Winwood in forming Blind Faith, opting to invite Ric Gretch from the band Family to play bass.