Who Were the Druids? Demystifying the Mystics of the Ancient Celtic World

painting of a druid in white robes being led in a procession

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A staff-wielding wizened old man with a chest-length beard in a long billowy robe. That is the popular image of the druid, that ancient caste of Celtic spell-caster. But how do the druids of our imaginations measure up against the genuine item? 

It’s a trickier question than one might think. As British archaeologist and academic Barry Cunliffe pointed out in his Very Short Introduction to the subject, “druid” meant different things at different times:

“Each generation interprets the Druids according to their own perspectives and prejudices, and therein lies one of the fascinations of the subject… Over the 800 years or so from c. 400 BC to AD 400, the Druid caste changed dramatically, as did the society of which they were a part. The last 500 years has seen our vision of them change equally as rapidly.”

source: Druids: A Very Short Introduction

One misconception we can immediately dispel is that the druids were solely concerned with the religious affairs of the Celtic peoples they served, that their principal function was that of pagan high priest. This was not the case. As historian Peter Berresford Ellis argued in his A Dictionary of Irish Mythology:

“[The druids] have been mistakenly called ‘a religious caste’. It is true that druids presided at religious functions and promulgated the Celtic religion and its rites. However, they were also important political figures, advisers, judges and teachers.”

Add to that list “lawyers,” “natural scientists,” “astronomers,” and  “moral philosophers,” and you’ll have a closer approximation of the many hats druids wore. 

As experts on both tribal law and “international” law, the druids regularly made legal, military, and political judgments and were often called upon to settle territorial disputes. In their heyday, the druids even had the power to prevent opposing tribes from going to war, as their legal and moral authority was greater than that of the chieftains or kings.

Yes, the druids wielded serious power in the ancient Celtic world, and — as lame as this is going to sound — their power stemmed from their knowledge.


Druid: Definition and Etymology

Two Druids, 19th-century engraving based on a 1719 illustration by Bernard de Montfaucon, who said that he was reproducing a bas-relief found at Autun, Burgundy.[1]

If I were forced, at staff-point, to give a concise, all-encompassing definition of “druids,” it would be as follows:

Druids were powerful, intellectual elites who served as the arbiters of truth and justice amongst their Celtic clans. In cases where human lives hung in the balance, druids effectively took on the roles of judge and jury (and perhaps even executioner on occasion). As philosophers and leaders of Celtic spiritual life, druids preached the immortality and transmigration of the soul, i.e, the concept that souls travel to another world — the Otherworld -— after death. As scientists and astronomers, druids studied the movement of celestial bodies and developed both lunar and solar calendars. Becoming a druid required up to twenty years of study, and druidic knowledge was passed on orally. There were no syllabi, no scrolls. Just words and memory.

The philologist Rudolf Thurneysen argued that the word “druid” comes from the roots dru and vid, translating loosely to “thorough knowledge” or “those with very great knowledge”. Pliny the Elder, on the other hand, put forth centuries earlier that “druid” is derived from the Greek word for oak, dru. Assuming the second element stems from the root wid meaning ”to know,” druid approximates to “those with knowledge of the oak” or “knower of the oak.”

Note: I’ve also seen it written that druid is derived from the Old Celtic root words deru, meaning oak tree, and weid, meaning to see or know. But perhaps Pliny is making the case that the Celts borrowed those words from the Greeks, which is certainly possible as the two cultures interacted with one another quite a bit. There’s even a theory out there, courtesy of Clement of Alexandria, that Celtic druids taught the Greek philosopher and mathematician Pythagoras—yes, that Pythagoras—their concept of the eternal soul, which he soon adopted himself. But I digress…)

The “oak-knower” etymology is especially fitting given that druids often practiced their rites in oak groves, and could sometimes be found munching on oak acorns. And then there’s that druidic obsession with mistletoe growing on oak trees. In the only-ever eyewitness account of an ancient druidic ceremony, Pliny tells of a white-robed druid climbing an oak tree and slicing mistletoe from its boughs with a golden sickle. The mistletoe is caught in a white cloth. Then a pair of oxen are slaughtered. But really, the ceremony isn’t about the oxen or even the mistletoe (which is a parasitic plant), it’s about the trees. To quote Pliny:

“The Druids – for so [the Celts’] magicians are called – held nothing more sacred than the mistletoe and the tree that bears it, always supposing that tree to be the oak. But they choose groves of oaks for the sake of the tree alone, and they never perform any of their rites except in the presence of a branch of it.”

source: Naturalis Historia

Historical Druids

Druids Inciting the Britons to oppose the landing of the Romans – from Cassell’s History of England, Vol. I – anonymous author and artists

The earliest druids we have evidence for, those documented by ancient Mediterranean writer-explorers who went traipsing around Gaul in the 4th century BCE and onward, were renowned for their philosophical prowess. To quote Cunliffe:

“What stands out from these early accounts is the respect the Greek writers clearly had for the Druids: the emphasis is on the Druids as philosophers – men who ranked high among the thinkers in the barbarian world outside the narrow Greek sphere. They are listed among the wise men of the world – the Egyptians, Assyrians, Bactrians, Persians, and Indians – men of honour and justice, the philosophers of the people.”

source: Druids: A Very Short Introduction

In his Geographica, first published in the first century BCE, Strabo continued the druid-as-philosopher theme. But the Greek philosopher, historian, and geographer also added some intriguing details about the way ancient Celtic society was structured. Specifically, Strabo distinguished between three classes or castes of special honor: bards (poets/singers), vates (seers), and druids. Here’s what he had to say about the latter group:

“The Druids, in addition to the science of nature, study also moral philosophy. They are believed to be the most just of men and are therefore entrusted with the decisions of cases affecting either individuals or the public … These men, as well as other authorities, have pronounced that men’s souls and the universe are indestructible though times of fire or water may prevail.”

source: Geographica Vol. 4

By the end of the first century CE, druids had developed a reputation for the tremendous amount of power and influence they wielded. It is from the Greek Stoic rhetorician Dio Chrysostom, writing in that era, when we learn about Celtic kings deferring judgment to their druids.

“The Celts appointed Druids, who likewise were versed in the art of seers and other forms of wisdom without whom kings were not permitted to adopt or plan any course so that it was that those who ruled and the kings became their subordinates and instruments of their judgment.”

source: Oratio

Roman soldiers killing druids and burning their groves on Anglesey, as described by Tacitus

Cunliffe advises, however, that we take Dio Chrysostom’s account with a grain of salt, as the rhetorician notoriously hated Rome’s ruling elite and envisioned a golden age when the wisest members of society were put in charge.

Here’s another bit of Celtic history that should be taken with a grain of salt, this one courtesy of Julius Caesar. According to Caesar, druids had their de facto headquarters—their main campus if you will— in Britain.

“It is thought that the doctrine of the Druids was invented in Britain and was brought from there to Gaul; even today those who want to study the doctrine in greater detail usually go to Britain to learn there.”

source: Commentarii de Bello Gallico VI.13

According to Cunliffe, we can only speculate as to how Caesar came to believe this. And at the same time, we must consider the possibility that he was right. To quote Cunliffe:

“Britain was an island redolent of ancient religious practice; perhaps his informants had access to oral traditions that spoke of these times.”

Because the druids of the ancient Celtic world passed down their sacred knowledge and traditions orally, the few written sources we have concerning that knowledge and those traditions come from outside observers; people with their own agendas and prejudices. Heck, Caesar referred to the gods of the Gaulish Celts by the names of their closest Roman equivalents (as opposed to calling them by their native, Celtic names). He observed that they worshipped Mercury (Visucius) most of all, followed by Apollo (Belenus), Mars (Lenus), Jupiter (Poeninus), and Minerva (Sulis).

This Romanization of Gaulish belief would be mirrored in the Christianization of Irish belief.


The Druids of Irish Myth

Apart from those classical sources we learned about in the previous section (Pliny, Strabo, Caesar, etc.), the other significant body of work we have that details the lives and roles of druids comes from Irish mythology. 

To clarify, Irish mythology — like Welsh, Cornish, Breton, Manx, and Scottish mythology — is an offshoot of the Celtic mythology propagated by the Gauls. One needs only look at the pantheon of Celtic gods and their cognates in Ireland (and other Celtic nations) to see the interconnectedness. For example, the god Lugh (or Lug) from Irish mythology and the god Lleu (or Llew) from Welsh mythology are both clearly derived from the same Gaulish sun god Lugus (or Lugos). Same with the Irish god Ogma (or Oghma) and the Welsh god Eufydd fab Dôn, who are both derived from Ogmios, the Gaulish god of eloquence.

Irish god Lugh and Welsh god Lleu are both descended from the Celtic god Lugus

To quote historian Peter Berresford Ellis:

“The fact that one can see relationships and counterparts demonstrates that Irish mythology is not a separate entity from the rest of the Celtic world. In it we find echoes of a common Celtic mythological, religious and, perhaps, historical experience.”

source: A Dictionary of Irish Mythology:

In some ways, the druids described in Irish myths align with those we learned about from classical sources. They are elite intellectuals and royal advisers who, through their knowledge, may wield more power than the kings and chieftains they ostensibly serve. For example, in the Ulster Cycle (a.k.a. Red Branch Cycle) of Irish mythology it is stated that no one was allowed to speak in the presence of the Ulster king Conchobar mac Nessa lest the king had spoken first. There was one exception to the rule: Conchobar’s druid Cathbad. When in the presence of the druid, it was the king who waited to speak.

However, the Irish myths also add a new, supernatural dimension to druids. Instead of appearing as “merely” highly educated elites, the Irish druids are wizards, casters of spells, masters of the dark arts, and in Cathbad’s case, seers of the future. Cathbad famously prophesized the incredible life of adventure the Irish hero Cú Chulainn would lead. And he also foresaw the brevity of that life.

Arguably the first druid to appear on Ireland’s shores (at least in Irish mythology) is Amergin Glúingel, a member and chief negotiator of the invading Milesian force. When the old Irish gods, the Tuatha de Danann, renege on a deal and brew up a magical storm of protection, it’s up to Amergin to sing an enchanted song invoking the spirit of Ireland. The druid’s song is powerful enough to part the divine storm and Amergin and his Milesians make it safely to shore.

Croome Park, Worcs: Druid statue in the park

But what do we make of stories like these? And from what time period do they come? To quote Barry Cunliffe:

“[T]he sagas were kept alive by oral transmission through the performances of storytellers. How deeply rooted in the past they were it is impossible to say for certain, but scholars are generally agreed that the sagas of the Ulster Cycle were being proclaimed at least as early as the early 5th century AD and are likely to be considerably older.”

source: Druids: A Very Short Introduction

What we do know for certain is that Christian monks were the first to commit Irish mythology to writing. Or rather, their sources are the oldest written sources we have. Unlike with the Gaulish druids, the Irish druids didn’t appear to have a taboo against the written word. In the myths, Irish druids regularly write in Ogham script on wooden staffs. Alas, wooden staffs wouldn’t survive for thousands of years, which perhaps explains their absence from the historical record.

Of course, we must remember that this is mythology we’re dealing with here. It’s hard to know what’s based in fact and what’s purely fictional. To quote Irish archaeologist and academic Barry Raftery:

“[T]he Irish sources present us with an immense body of material combining fact and fantasy, myth and legend, ancient lore, Classical interpolation, pan-Christian fables and medieval folk tradition. As a source of information on the Irish Iron Age it provides us with a challenge of exceptional complexity.”

source: Pagan Celtic Ireland

That being said, scholars agree that druids were active in ancient Ireland, just as they were in ancient Britain. (Remember King Arthur’s most trusted adviser, Merlin? That character was based on a real, local druid.) As Cunliffe explained, Irish druids are “attested in the Lives of the saints, in hymns, and in Law tracts codified in the 7th and 8th centuries—though by this time they are so reduced by Christianity as to be regarded as little more than magicians and witch doctors…The mood is captured by one 8th-century hymn that asks for God’s protection from the spells of women, blacksmiths, and Druids!”

It’s obvious that Ireland’s Christian monks, in their transcribing, put their own stamp on the druidic traditions described in Irish myths. The transformation of druids from intellectuals to wizards was a deliberate and calculated move on the part of the Church. Think about it: If you’re the clergy, you can’t recognize an elite class of pagans as the arbiters of truth and justice—that’s your job. 


Passing the Tonsure: From Druid to Priest

The rise of Christianity in Ireland ultimately meant the end of Irish druidsm. Yes, you can still find people who call themselves druids in Ireland (and all over the world, for that matter), but neodruidism is a separate subject, one largely divorced from the history we’ve been exploring. The reality is that in Ireland, as in the rest of the Celtic world, the roles and reputations of druids were gradually reduced as Christianity gained traction.

Druids Inciting the Britons to oppose the landing of the Romans – from Cassell’s History of England, Vol. I – anonymous author and artists

But old habits die hard. And by “habits,” of course, I’m referring to the long, loose garments worn by members of religious orders. Because as it turns out, Christian monks in Ireland copied the fashion of their Celtic predecessors. Although to be fair, they didn’t copy the robes (everyone was wearing robes back then), they copied the haircuts. To quote Ellis:

“Druids in Ireland had a tonsure, as did the later Christian monks. It is recorded that they cut their hair in a mystic figure called airbacc Giunnae (perhaps, fence cut of the hair) — a tonsure which ran from ear to ear instead of being a circular form on the crown of the head. The Celtic Christian monks copied this fashion and it became one of the points of contention with Rome. The Roman form of tonsure finally displaced the Celtic form.”

Stories abound of St. Patrick battling druids. In one yarn, spun several hundred years after Patrick’s death, the Apostle of Ireland is in a Gandalf-vs.-Saruman-style showdown with a druid and sends the druid flying through the air. The druid crashes to the ground and breaks his skull. Most scholars agree that such stories are not to be trusted. 

image of st. patrick in blue cassock
The earliest known image of St. Patrick (circa the 13th century) (source: Smithsonian)

The reality is St. Patrick likely wore the tonsure of the Irish druids. And he didn’t fight druids, he recruited them. To quote professor and folklorist Juilene Osborne-McKnight: 

“[Patrick’s] ‘biographers’—two monks named Tirechán and Muirchu, as well as many later hagiographers—mythologized Patrick into someone he never was: a man who fought with druids, used shamrocks to teach the trinity, and drove the snakes from Ireland. In truth, many druids became priests of the new religion…”

source: The Story We Carry in Our Bones: Irish History for Americans

They were the perfect fit, really. Spiritual and judicious. Disciplined. Already revered among the locals. Irish druids were the perfect candidates to teach that newfangled Christian religion to their Irish pagan followers.

And yes, they had those awesome haircuts.


Further Reading

The World of the Druids by Miranda J. Green

The Druid Animal Oracle by Philip and Stephanie Carr-Gomm

The Druid Plant Oracle: Working with the Magical Flora of the Druid Tradition by Philip and Stephanie Carr-Gomm


Want to learn about the darker side of Irish mythology? Check out…

Samhain in Your Pocket (Celtic Pocket Guides 2)

Perhaps the most important holiday on the ancient Celtic calendar, Samhain marks the end of summer and the beginning of a new pastoral year. It is a liminal time—a time when the forces of light and darkness, warmth and cold, growth and blight, are in conflict. A time when the barrier between the land of the living and the land of the dead is at its thinnest. A time when all manner of spirits and demons are wont to cross over from the Celtic Otherworld. Learn more…


Neon Druid: An Anthology of Urban Celtic Fantasy

“A thrilling romp through pubs, mythology, and alleyways. NEON DRUID is such a fun, pulpy anthology of stories that embody Celtic fantasy and myth,” (Pyles of Books). Cross over into a world where the mischievous gods, goddesses, monsters, and heroes of Celtic mythology live among us, intermingling with unsuspecting mortals and stirring up mayhem in cities and towns on both sides of the Atlantic, from Limerick and Edinburgh to Montreal and Boston. Learn more…


More the listenin’ type?

I recommend the audiobook The Path of Druidry: Walking the Ancient Green Way by Penny Billington (narrated by Jennifer M. Dixon). Use my link to get 3 free months of Audible Premium Plus and you can listen to the full 15-hour audiobook for free.


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