A druid was a member of the high-ranking priestly class in ancient Celtic cultures. Druids served as religious leaders, judges, keepers of knowledge, medical professionals, and political advisors. They did not leave any written records. Although they were believed to be literate, their religious beliefs may have prevented them from writing down their knowledge. Information about their beliefs and practices was recorded in detail by people from other cultures, such as the Romans and the Greeks.
The earliest known references to druids date to the 4th century BCE. The oldest detailed description of them comes from Julius Caesar’s writings about the Gallic Wars in the 50s BCE. Other Roman writers, including Cicero, Tacitus, and Pliny the Elder, also described druids. After the Roman invasion of Gaul, the Roman government, under emperors Tiberius and Claudius in the 1st century CE, suppressed druid groups. By the 2nd century, druids were no longer mentioned in written records.
In about 750 CE, the word "druid" appeared in a poem by Blathmac, who wrote about Jesus, stating that Jesus was "better than a prophet, more knowledgeable than every druid, a king who was a bishop and a complete sage." Druids are often mentioned in stories from Irish mythology, first written down by monks and nuns of the Celtic Church, such as "Táin Bó Cúailnge" (12th century). Later Christian legends often portrayed druids as magicians who resisted the spread of Christianity by missionaries. During the Celtic revival in the 18th and 19th centuries, groups based on ideas about ancient druids were formed, a movement called Neo-Druidism. Many common beliefs about druids, based on incorrect ideas from 18th-century scholars, have been replaced by more recent research.
Etymology
The word "druid" in modern English comes from the French word "druide," which itself is from the Latin word "druida" (only found in the plural form "druides"). This Latin word was likely borrowed from the Gaulish language, which used "druid-." The Old English word "drȳ," meaning a magician or wizard, was borrowed from Celtic languages, possibly from Irish or Brythonic.
The Gaulish word "druides" is related to the Old Irish word "druí" (plural "druíd," meaning "magician" or "wizard") and may also be connected to the Middle Welsh word "dryw," meaning "seer" (as found in the Book of Taliesin). In both Irish and Welsh, "druí" and "dryw" could sometimes refer to the wren, a bird seen as prophetic in these traditions. The Middle Welsh word "derwydd" (meaning "seer") and the Old Breton word "dorguid" (meaning "prophetic" or "magical") show similar patterns. These may reflect a change in the Proto-Celtic word "dru-wid-" to "daru-wid-" (based on the Celtic word "daru-" meaning "oak tree") or could come from "do-are-wid-" (meaning "who sees beyond").
All these forms come from a reconstructed Proto-Celtic noun "dru-wid-s" (plural "dru-wid-es"). The second part of the word is usually linked to the Proto-Indo-European (PIE) verb "weyd-" meaning "to see" or "to know." The origin of the first part has been debated by scholars. Most believe it comes from the PIE word "derw-" or "*dru-" meaning "oak tree," which also metaphorically meant "strong" or "firm." Based on this, the word has been interpreted in different ways, such as "oak-knower," "someone who knows trees," "someone who knows the world-tree," or "a priest with strong insight." This idea was noted by Pliny, a writer from the 1st century, who compared the first part of the word to the Greek word "drŷs" meaning "oak." Some scholars, however, suggest the first part might be an intensive prefix, meaning "very wise."
Practices and doctrines
Ancient and medieval writers describe the religious duties and social roles of druids. Greco-Roman and Irish sources agree that druids were important in pagan Celtic society. Julius Caesar wrote that druids were among the two most important groups in the region, along with the nobles, and were responsible for organizing religious practices, divination, and legal matters in Gallic, British, and Irish societies. He noted that druids were not required to serve in the military or pay taxes and could exclude people from religious events, making them social outcasts. Diodorus Siculus and Strabo wrote that druids were so respected that they could stop battles if they intervened between two armies.
Diodorus described druids as "philosophers" and "learned in religious affairs," while Strabo said their knowledge included natural and moral philosophy. Ammianus Marcellinus listed them as experts in "obscure and profound subjects." Pomponius Mela was the first to mention that druidic education was secret and took place in caves and forests. Cicero wrote about a Gaulish druid who claimed to understand nature, using augury and predictions.
Druidic knowledge included memorized verses, and Caesar said it could take up to twenty years to learn. No ancient verses from druids are known to have survived. Instruction was oral, but the Gauls used Greek letters for writing. By Caesar’s time, writing had shifted to Latin letters. Caesar believed druids kept their knowledge secret to protect it and improve memory. He noted that many young men chose to study with druids, while others were sent by families due to their privileges.
Greek and Roman writers often mentioned druids practicing human sacrifice. Caesar said criminals were preferred as victims, but innocent people were used if criminals were unavailable. One method involved burning victims alive in a wooden figure, now called a wicker man. A 10th-century text, Commenta Bernensia, described sacrifices to gods as drowning, hanging, and burning. Diodorus Siculus said druids acted as intermediaries between people and gods, using animal sacrifices and observing human victims to predict the future.
Archaeological evidence from western Europe, such as mass graves in Gaul, has been linked to human sacrifice. Some experts, like Jean-Louis Brunaux, believed these were sacrifices to a war god, while others, like Martin Brown, thought they were honored warriors. Historians debate whether Roman and Greek writers accurately described druids, as these cultures sometimes exaggerated foreign practices. Nora Chadwick, an expert in medieval literature, suggested that claims of druidic sacrifice were Roman propaganda.
Alexander Cornelius Polyhistor called druids philosophers and described their belief in the immortality of the soul, a concept linked to Pythagorean ideas. Caesar wrote that druids taught the soul’s immortality, believing it moved to new bodies after death. He also noted their studies of stars, geography, and religion. Diodorus Siculus, writing in 36 BCE, confirmed druids followed the Pythagorean belief in soul reincarnation. In 1928, Donald A. Mackenzie speculated that Buddhist missionaries from India may have influenced druids. Caesar mentioned druids believed the tribe’s ancestor was a god called "Dispater," meaning "Father Dis." Diogenes Laertius wrote that druids used riddles and teachings to promote worship, morality, and courage.
Druids in mythology
Druids are important figures in Irish folklore. They often served as religious advisors to kings and lords, using their abilities to predict the future and perform other mystical tasks. One well-known druid is Cathbad, who was the chief druid in the court of King Conchobar mac Nessa of Ulster. Cathbad appears in many stories, most of which describe his ability to foresee events. In the tale of Deirdre of the Sorrows, a key character in the Ulster Cycle, Cathbad told the court that Deirdre would grow up to be very beautiful. He also predicted that kings and lords would fight over her, that much blood would be spilled because of her, and that Ulster's three greatest warriors would be forced into exile for her. The king ignored this warning, but the prophecy came true.
Another important druid was Amergin Glúingel, a bard and judge for the Milesians in the Mythological Cycle. The Milesians tried to take control of Ireland from the Tuatha Dé Danann. When the Milesians arrived, the druids of the Tuatha Dé Danann created a magical storm to stop their ships from landing. Amergin responded by calling upon the spirit of Ireland, reciting a powerful chant known as The Song of Amergin. After successfully reaching Ireland, he helped divide the land among his royal brothers during the conquest, earning the title Chief Ollam of Ireland.
Other notable druids include Tadg mac Nuadat from the Fenian Cycle and Mug Ruith, a blind druid from Munster known for his great power.
Female druids
Irish mythology includes many female druids who held important cultural and religious roles similar to their male counterparts. The Irish language has several terms for female druids, such as bandruí ("woman-druid"), mentioned in stories like Táin Bó Cúailnge. Another example is Bodhmall, a character from the Fenian Cycle and one of Fionn mac Cumhaill’s childhood caretakers. Tlachtga, the daughter of the druid Mug Ruith, is linked to the Hill of Ward, a place where festivals were held in her honor during the Middle Ages.
Another bandruí, Biróg, plays a key role in a folktale where the Fomorian warrior Balor tries to stop a prophecy by imprisoning his daughter Eithne on Tory Island to keep her away from men. Bé Chuille, the daughter of the goddess Flidais, appears in a story from the Metrical Dindshenchas, where she helps three other Tuatha Dé Danann members defeat the Greek witch Carman. Other bandrúi include Relbeo, a Nemedian druid described in The Book of Invasions as the daughter of a Greek king and the mother of Fergus Lethderg and Alma One-Tooth. Dornoll, a bandrúi in Scotland, trained warriors like Laegaire and Conall and was the daughter of Domnall Mildemail.
Classical writers such as Artemidorus Ephesius and Strabo mentioned the Gallizenae (or Gallisenae), virgin priestesses from the Île de Sein near Pointe du Raz in western Brittany. They lived on an island forbidden to men, but they visited the mainland to meet their husbands. Their religious beliefs and the deities they honored are unknown. Pomponius Mela described the Gallizenae as skilled in healing and as advisors who could control the sea and wind through incantations, change into animal forms, and predict the future. They only helped sailors who sought their guidance.
According to the Historia Augusta, the Roman emperor Alexander Severus received a prophecy about his death from a Gallic druidess (druiada). The same text records Emperor Aurelian asking druidesses about the fate of his descendants, and they predicted it would favor Claudius II. Flavius Vopiscus also wrote that Emperor Diocletian received a prophecy from a druidess of the Tungri.
Sources on druid beliefs and practices
The earliest known written records about druids come from ancient Greece and Rome. Archaeologist Stuart Piggott compared how these ancient writers viewed druids to how Europeans in the 15th and 18th centuries described societies they encountered in places like the Americas and the South Sea Islands. He noted that both groups saw these societies as less advanced in technology and social development.
Historian Nora Chadwick grouped the ancient descriptions of druids into two categories. The first group, called the "Posidonian" tradition, was named after a writer named Posidonius. This group criticized the Iron Age societies of Western Europe, calling them "barbaric." The second group, called the "Alexandrian" tradition, came from the educational traditions of Alexandria, Egypt. This group viewed these societies more kindly and idealized them. Piggott connected this to ideas called "hard primitivism" and "soft primitivism" studied by other historians.
Some scholars believe the ancient accounts of druids may not be accurate and could be fictional. They argue that druids might have been invented by Roman and Greek writers to describe people they saw as "barbarians," helping justify Roman expansion into these regions.
The earliest known records of druids appear in two Greek writings from around 300 BCE. These texts, written by Sotion of Alexandria and attributed to Aristotle, are now lost but were quoted by a writer named Diogenes Laërtius in the 2nd century CE.
Diogenes Laërtius wrote that some ancient people believed philosophy began with groups outside of Greece, such as the Magi in Persia, the Chaldaei in Babylon or Assyria, the Gymnosophistae in India, and the druids among the Celts and Gauls. He included these ideas in his work Vitae.
Later Greek and Roman writings from the 3rd century BCE mention "barbarian philosophers," possibly referring to the Gaulish druids.
The first detailed written description of druids comes from Julius Caesar’s Commentarii de Bello Gallico, written in the 50s or 40s BCE. As a Roman general, Caesar described druids as people who focused on religious practices, sacrifices, and interpreting rituals. He said they were respected members of Gaulish society, along with a class called the equites. They also acted as judges.
Caesar wrote that druids followed a leader who ruled until his death, after which a new leader was chosen. They met annually at a sacred place in the territory of the Carnutes, believed to be the center of Gaul. They saw Britain as the heart of druidic learning and said druids were not found among the German tribes east of the Rhine. Caesar noted that young men studied to become druids, memorizing their teachings. He claimed their main belief was that souls passed from one body to another after death. They studied the stars, the cosmos, nature, and the gods, showing knowledge of astronomy, theology, and cosmology. Caesar also said druids oversaw human sacrifices, often using criminals, and that victims were burned inside a wicker man.
Modern historians have criticized Caesar’s account as possibly inaccurate. Some, like Fustel de Coulanges, pointed out Caesar never mentioned druids in his writings about conquering Gaul, nor did Aulus Hirtius, who continued Caesar’s work. Historian Ronald Hutton suggested Caesar portrayed druids as both civilized (knowledgeable and religious) and barbaric (practicing human sacrifice) to justify Roman rule. Others, like Sean Dunham, argued Caesar compared druids to Roman senators. Daphne Nash believed Caesar exaggerated the centralization of druidic leadership and their connection to Britain.
Some historians believe Caesar’s account might be more accurate. Norman J. DeWitt suggested Caesar described an idealized version of druidic society from the 2nd century BCE, before major conflicts changed Gaul. John Creighton noted druidic influence in Britain may have declined by the mid-1st century BCE due to new power structures. Miranda Aldhouse-Green argued Caesar’s account is one of the most reliable sources about druids, even if he may have exaggerated details to support Roman expansion.
Other ancient writers also wrote about druids. Cicero, a contemporary of Caesar, mentioned meeting a Gallic druid named Divitiacus of the Aedui tribe. Divitiacus was said to understand nature and practice augury. However, some question whether he was truly a druid, as Caesar never called him one and described him as a political and military leader.
Diodorus Siculus, another ancient writer, described druids in his Bibliotheca Historica, published in 36 BCE. He called them drouidas and compared them to philosophers and theologians, noting their roles alongside poets and singers.
Archaeology
As historian Jane Webster explained, "it is hard to find proof of individual druids through archaeology." A.P. Fitzpatrick studied symbols he thought might relate to the stars or heavens on late Iron Age swords. He found it difficult to connect these objects, even the Coligny calendar, to druidic culture.
Some archaeologists have tried to connect discoveries with written records about druids. Anne Ross linked evidence of human sacrifice in Celtic society, such as the Lindow Man bog body, to descriptions by Greco-Roman writers that said druids presided over such rituals. Miranda Aldhouse-Green, a professor of archaeology at Cardiff University, noted that Suetonius’s army likely passed near the Lindow Man’s location while traveling to deal with Boudicca. She suggested the sacrifice might be connected to this event. In 1996, a skeleton found with advanced medical tools and possibly religious items was called the "Druid of Colchester."
An excavation in Deal, Kent uncovered the "Deal Warrior," a man buried around 200–150 BCE with a sword, shield, and a rare headband. The headband was made of thin bronze, with a wide band around the head and a narrow strip across the top. Hair was found on the metal, showing it was worn directly on the head without padding. The style of the headdress is similar to images of Romano-British priests from centuries later. This has led some archaeologists to suggest the man might have been a religious official, possibly a druid.
History of reception
During the Gallic Wars from 58–51 BCE, the Roman army, led by Julius Caesar, conquered the many tribal chiefdoms of Gaul and added it to the Roman Republic. Later accounts from centuries after this event describe how the new rulers of Roman Gaul introduced laws to remove the druids from the region. According to Pliny the Elder, who wrote in the 70s CE, Emperor Tiberius (ruled 14–37 CE) passed laws that banned not only druidic practices but also other native soothsayers and healers. Pliny believed this would stop human sacrifices in Gaul. Suetonius, writing in the 2nd century CE, noted that Rome’s first emperor, Augustus (ruled 27 BCE–14 CE), made it illegal for anyone to be both a druid and a Roman citizen. Later, Emperor Claudius (ruled 41–54 CE) passed a law that "thoroughly suppressed" the druids by banning their religious practices.
The strongest evidence of a druidic tradition in the British Isles comes from the Celtic word druwid-, which appears in Insular Celtic languages. In Old Irish, it means "magic," and in Welsh, it means "seer."
The druids, who were a priestly group, disappeared in Wales after the region became Christian by the 7th century at the latest. However, roles like the bard and "seer" (Welsh: dryw) continued in medieval Wales until the 13th century.
Minister Macauley (1764) reported finding five druidic altars, including a large circle of stones near Stallir House on Boreray, which is part of the westernmost settlement in the UK, St. Kilda.
Classics professor Phillip Freeman discussed a later reference to "dryades," which he translated as "druidesses." He noted that the Historia Augusta, a 4th-century CE collection of imperial biographies, mentions three short passages about Gaulish women called "dryades." These women may not have been direct descendants of the druids, but they show that the druidic role of prophecy continued among the people of Roman Gaul. Female druids are also mentioned in later Irish mythology, such as in the legend of Fionn mac Cumhaill, who was raised by the woman druid Bodhmall and another wise-woman, according to The Boyhood Deeds of Fionn from the 12th century.
The story of Vortigern, as told by Nennius, gives one of the few accounts of druids possibly surviving in Britain after the Romans arrived. Nennius wrote that after being excommunicated by Germanus of Auxerre, Vortigern invited twelve druids to help him.
In stories about saints and martyrs, druids are described as magicians and diviners. In Adamnan’s life of Columba, two druids act as tutors to the daughters of Lóegaire mac Néill, the High King of Ireland, when Saint Patrick arrives. They try to stop Patrick and Saint Columba by creating clouds and mist. Before the battle of Culdremne in 561 CE, a druid made an airbe drtiad, which might have been a "fence of protection," though the exact meaning is unclear. Irish druids had a unique way of cutting their hair. The word druí was used to translate the Latin word magus (meaning "magician"), and in one passage, Saint Columba refers to Jesus as his druid. A life of Saint Beuno mentions that when he died, he had a vision of "all the saints and druids."
Sulpicius Severus’s life of Martin of Tours describes how Martin saw a peasant funeral and mistook it for druidic rituals. He stopped the procession by showing his cross, causing the people to freeze and then spin in confusion before allowing them to continue.
From the 18th century, interest in druids grew in England and Wales. John Aubrey (1626–1697) was the first modern writer to incorrectly link Stonehenge and other ancient monuments with druids. William Stukeley (1687–1765) later popularized this idea. John Toland (1670–1722) is wrongly believed to have founded the Ancient Druid Order, but historian Ronald Hutton found that the order was actually created in 1909 by George Watson MacGregor Reid. The order never used the title "Archdruid" and falsely claimed William Blake was its "Chosen Chief" from 1799–1827, though no evidence supports this. Blake’s mystical ideas came from other sources, not druids. Toland was influenced by Aubrey’s theories about Stonehenge but did not credit him. In 10th-century Wales, the roles of bards were established by Hywel Dda, and the idea that druids were their predecessors arose in the 18th century.
In the 19th century, some people incorrectly believed, based on reading The Gallic Wars, that druids were the main group resisting the Romans in Gaul during the 1st century BCE. This idea was later dismissed by scholars, though it remains in folk history.
Druids became widely known in popular culture during the Romanticism movement. In Chateaubriand’s novel Les Martyrs (1809), a druid priestess falls in love with a Roman soldier, though the story focuses on the triumph of Christianity over paganism. Opera from the early 19th century also featured druids, such as in Giovanni Pacini’s La Sacerdotessa d'Irminsul (1817), which told the story of a druid priestess. Vincenzo Bellini’s opera Norma (1831) was initially a failure but later became popular in London. The story reused elements from earlier druidic themes.
A key figure in the 19th-century revival of druidic interest was Edward Williams, a Welshman known as Iolo Morganwg. His writings, published after his death, were not accepted as credible by scholars. He claimed to have collected ancient knowledge from a group he called the "Gorsedd of Bards of the Isles of Britain." His works, The Iolo Manuscripts (1849) and Barddas (1862), are not considered reliable by modern researchers.