Chuck Berry essentially invented rock and roll music, and is perhaps the most important person in the history of rock. Elvis took the music and did it well, but to put him in the same sentence as Chuck Berry completely discredits Berry. Berry created and innovated a genre. Elvis performed black music well, made it white (opening doors for Beatles, etc) and brought sex appeal to it. Berry essentially designed it, Elvis made it grow. Elvis was a performer, Berry was a creator.
Fyi, self anointed or anointed nicknames are silly. Elvis was referred to as the king of rock, doesn't mean he. Jackson anointed himself the king of pop, doesn't mean he was. As a joke on this whole concept, Howard Stern anointed himself the king of all media. It is nothing more than a nickname, funny that after awhile people begin to act like its a credible title.

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