We've been through all this before. "Fretless" has it. I'll just add that best evidence is that the Celts were a cultural, not racial grouping; and that there was no single "Celtic Race", in the same way that there is no single "European Race", though there were several distinct racial groups described by the Romans as Celts. Modern usage has tended rather to ignore all that and develop a romanticised ideal which isn't really borne out by the historical record.

I had better go into hiding now, before somebody brains me with their celtic didgeridoo.