"Although many bands from The British Invasion could have fallen under the banner of punk had they been born a few years later, the seeds were already being planted from something heavier on the horizon. Artists like The Stooges had already been exposing people to heavier flavours of rock, and looking at the more raucous songs by The Beatles and The Rolling Stones like ‘Helter Skelter’, it wasn’t like there was no room for something more aggressive on the charts."
January 1, 1970
https://en.wikiquote.org/wiki/Heavy_metal_music_before_1970