Pick pretty much any topic on the planet, and you can go straight to Google with as many questions as you like, emerging from your search with answers from at least a few solid original sources. A glaring exception to this fact-finding rule of thumb? The Druids.
"What is fascinating is how little we know about the Druids," emails Owen Jarus, who wrote about the topic for Live Science in 2014. "The written references we have are written by non-Druids and their writings may be affected by anti-Druid Roman sentiment. When and where the Druids originated and much about their practices remains unknown."
In fact, famed Roman general and statesman Julius Caesar is considered the world's preeminent expert on all things Druid, and the fact that he died in 44 B.C.E. may indicate just how little we actually know about the class of Celtic-speaking experts in magical and religious practice who inhabited northwestern Europe about 2,000 years ago.
"Because we don't have any accounts of Druids from early Celtic-speaking peoples themselves, there remains an air of mystery around them," Myriah Williams, a lecturer in Celtic studies at U.C. Berkeley, says in an email interview. "Perhaps this air of mystery is attractive; without concrete evidence of who Druids were and what their role in society was, they can be shaped to fit different molds for different purposes."
The basic definitions of Druidism as we know it can be tied to two main sources: ancient Greek and Roman writings and portions of medieval Irish literature. The first source has an advantage in that these writings originated from people who were actually alive at the time the Druids existed. The main issue, however, is that almost all these writings relied on secondhand information and none of it was very fleshed out.
"According to the accounts of Classical authors, who will have had their own biases and only some of whom may have been direct witnesses, Druids seem to have been a learned class of Celtic-speaking peoples who may have wielded some political authority and who acted as religious intermediaries," Williams says. "Poseidonius and other Greek sources describe them as philosophers. According to Caesar, they had to spend 20 years in training."
Caesar also said that there were two groups of men in Gaul (a historical region of Western Europe inhabited by Celtic tribes) that were considered honorable: the Druids and the noblemen, and that because Druids were in charge of public and private sacrifices, many people went to them for instruction. According to Britannica, "if anyone disobeyed their decree, he was barred from sacrifice, which was considered the gravest of punishments. One Druid was made the chief; upon his death, another was appointed. If, however, several were equal in merit, the Druids voted, although they sometimes resorted to armed violence." It's also thought that the Druids assembled annually to review all legal disputes.
The other main source of Druid knowledge — ancient Irish literature — has the advantage of being produced by a society that once included Druids and includes more frequent references to the group. But this source also has two big problems: Like the Greek and Roman texts, the ancient Irish texts also include widely varying depictions of Druids, so it's hard to glean whether they were considered wise, powerful figures or "savage pagan priests." The other main problem, according to History Today: "All the Irish texts were written, and perhaps composed, hundreds of years after the conversion of the Irish to Christianity when Druids had by definition ceased to exist."
What is known about Druids can be boiled down to their basic roles in society. Jarus credits scholar Sir Barry Cunliffe with much of what's known about the Druids today. "As Cunliffe wrote in his book, 'Druids: A Very Short Introduction,' the Druids performed a variety of roles including, 'philosophers, teachers, judges, the repository of communal wisdoms about the natural world and the traditions of the people, and the mediators between humans and the gods,'" Jarus says. "The ancient form of Druidism seems to have died out during the Middle Ages before being 'revived' centuries later, although there may be little to no continuity between ancient Druidism and more modern forms."