The Incredible String Band - WAY BACK IN THE 1960S
this is a time travel tune. i cannot think of another song that does this retro-active thing. back then we would listen and imagine it was now and we were listening to it decades later and..
my friends the incredibles were responsible for the career of led zep, and were studied by, especially, the beatles (sgt. p) and the stones (who's introduction of the sitar to rock 'n roll was filched from our beautiful people here).
genre?
world music (sorry peter g.) - of which, celtic folk rock could be regarded as an essential sub-catagory (with perhaps the suffix of psychedic:)