Druids. A sacerdotal caste which flourished in Britain and Gaul. They were Initiates who admitted females into their sacred order, and initiated them into the mysteries of their religion. They never entrusted their sacred verses and scriptures to writing, but, like the Brahmans of old, committed them to memory; a feat which, according to the statement of Cæsar took twenty years to accomplish. Like the Parsis they had no images or statues of their gods. The Celtic religion considered it blasphemy to represent any god, even of a minor character, under a human figure. It would have been well if the Greek and Roman Christians had learnt this lesson from the “pagan” Druids. The three chief commandments of their religion were:—“Obedience to divine laws; concern for the welfare of mankind; suffering with fortitude all the evils of life”.
Source: H.P.Blavatsky - The Theosophical Glossary