Here is a
from the website of the Order of Bards, Ovates and Druids, and I quote:
"
Celtic Reconstuctionism: this is the attempt to use archaeological data, records of the time and known history in order to reconstruct ancient Celtic beliefs and practices, to be followed as a religion or spirituality today. This practitioner wishes to resurrect ancient Celtic religion.
Celtic Revivalism: this is an attempt to practise a Celtic religion or spirituality within the context of the modern world, often cherry-picking the ‘best bits’ of ancient belief and merging it with traditions that are not Celtic. This practitioner wishes to embrace the (perceived) spirit of ancient Celtic religion."
It's all relative, of course. As far as ancient Greece is concerned, the textual and archeological evidence is of course incomperably better than in the case of the druids but I read somewhere that the common folk in ancient Greece had a superstitious fear of, not awe or admiration for, all those noble gods so gloriously described by Homer, the ancient Greek philosophers, playwrights and poets. And for that matter, how exactly did the early Christian worship when the Bible was not even compiled or widely disseminated yet? We just don't know. Religions are a man-made thing, and that becomes even more obvious as soon as people turn their back on firmly codified monotheism and call themselves '(Neo)Pagans' - they
believe what they want to believe. Karma? Like the idea, into NeoPaganism it goes. Reincarnation? Cool, let's throw it into the mix as well! Dress up in robes made out of fabrics that weren't even available in ancient 'barbarian' lands at that time? Love it, after all, that more authentic coarse wool feels so scratchy on the skin... and not even chieftains then would have been able to afford all that shiny jewelry.
I think that thanks to the internet, you cannot base a successful religion or cult on fake historical evidence anymore. Up to the 1980ies or so, every book on Wicca typically contained tearful description of those terrible Burning Times
as inaccurate or even mythical; however, the readers of those books sat alone in their rooms fuming at the atrocious injustice of it all while the academics on their part published their findings in specialized journal, without those two groups ever coming into contact with each other. Nowadays you can look up anybody's historical claims with a few minutes of googling, and the only strategy left to cult leaders or NewAge authors now is to claim 'privileged information' through (unverifiable) personal revelation. There are still deluded innocents who'll go along with this because as I said: people will believe what they
want to believe.