The Beatles

Innocuous and not so original until Rubber Soul, from then on an unstoppable pop group that took, mixed, and created a genre, never making clear from what points they started and what new points they created, uniting from light music a vast array of genres and creating their own style. Highly imitated. And now increasingly imitated in a downward trend, unfortunately mainstream pop has hit rock bottom, but it wasn't always the crap that people think.