Pleas don't include Deep Purple,there early material before 'IN ROCK' may seem prog but it isnt.
I'd like to claim proto prog lead the way upto say '71/'72 where as bands such as ELP,Genesis,Yes etc started getting a bit too big for their boots which did'nt last long before they started falling to pieces.I try not to listern to that commercialised prog junk anyway.
Can i just say that even though bands such as Uriah Heep,Black Sabbath,Warhorse etc emerged through the then up & coming progressive labels they were not in anyway prog.
Proto prog arse...