Correct me if I'm wrong but I thought that the current trend in archaeology/anthropology/pre-historic studies/linguistics etc is to cast doubt on the existence of The Celts as an identifiable race. Rather to look upon pre-Roman Europe as being populated by many different tribes with migration, settlement and active trade as the way that implements and art were cross-pollinated. I did an evening class course about three years ago in archaeology and as far as my memory serves me our tutor only used the word Celts once.
Opinions anyone?