Quoted from o-din:For those that are calling Zep a rip-off band, they never denied being strongly influenced by Robert Johnson, Muddy Waters, etc. They were just one of the first. All rock and roll is stolen one way or another. Just think how many times Led Zeppelin has been borrowed from.
Not one of the first, they just did it best. The Yardbirds, Spencer Davis Group, Manfred Mann, Small Faces, Fleetwood Mac, Cream, Stones, Animals, etc. came before LZ playing American Blues straight ahead or rocked-up. Everyone borrowed riffs and ideas from their influences--still do. The big difference with Zeppelin--they blatantly ripped off existing tunes by bending around the music and/or slightly (or not so slightly) altering the lyrics. Not cool to claim these were then "original" compositions. It took a lawsuit or three years later to assign the writing credits to where they rightfully belonged. Others for whatever reason did not pursue legal action. Page was a master at putting together a great "new" song using other artists work. His work as a producer and session musician also gave him exposure to innumerable songs. Listen to the last recordings or live bootlegs of the Yardbirds with Page on guitar--you will hear the birth of Led Zeppelin, who did some of the same tunes as Page did with the Yardbirds (only now they were "Page" creations). Page was brilliant.