Well, there are plenty of references to druidry as such from contemporary
sources such as the Romans and early Christians who were both in opposition to
them. As when human sacrifice is attributed to druid rites, but may in reality
have been a separate pagan habit peculiar to Gaul & Germany.
Then there's neo-druidism which is a relatively modern creation, and pantheism
which often seems to overlay Tolkien's Christianity. But the one evolved in
parallel with the other.
As regards druidry, I was thinking of the classic accounts which Tolkien &
Graves would have been familiar
with.
