Conversation so far:
What is notable about the Beatles music style?
The Beatles' initial style was a highly original, irresistibly catchy synthesis of early American rock and roll and R&B.
Are there any other interesting aspects about the Beatles article?
In their initial incarnation as cheerful, wisecracking moptops, the Fab Four revolutionised the sound, style, and attitude of popular music.
What is the Fab Four in relation to the Beatles?
The Beatles acquired the nickname the Fab Four.

Question: Why did they revolutionize the sound of rock and roll?
Self-contained rewrite: Why did the Beatles revolutionize the sound of rock and roll?