A druid was a member of a high-ranking priestly group in ancient Celtic cultures. Druids served as religious leaders, judges, keepers of knowledge, doctors, and advisors to leaders. They did not leave written records. Although they were believed to be able to read and write, their teachings were not recorded in writing due to religious rules. Information about their beliefs and practices comes from descriptions by people from other cultures, such as the Romans and Greeks.
The first known mentions of druids date back to the 4th century BCE. The most detailed early description is found in Julius Caesar’s Commentarii de Bello Gallico, written in the 50s BCE. Other Roman writers, including Cicero, Tacitus, and Pliny the Elder, also wrote about 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 CE, druids no longer appeared in written records.
In about 750 CE, the word "druid" appeared in a poem by Blathmac, who compared Jesus to a druid, saying Jesus was "more knowledgeable than every druid." Druids are often mentioned in stories from Irish mythology, first written by monks and nuns of the Celtic Church, such as Táin Bó Cúailnge (12th century). Later Christian stories often portrayed druids as sorcerers who opposed the spread of Christianity. During the Celtic revival in the 18th and 19th centuries, groups inspired by ideas about ancient druids formed, leading to a movement called Neo-Druidism. Many common beliefs about druids, based on misunderstandings from 18th-century scholars, have been corrected 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" (used only in plural as "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 similar to the Old Irish word "druí" (plural "druíd," meaning "magician or wizard") and may also be related to the Middle Welsh word "dryw," meaning "seer" (found in the Book of Taliesin). In both Irish and Welsh, "druí" and "dryw" could sometimes refer to the wren, a bird believed to have prophetic powers 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 changes in the Proto-Celtic word dru-wid- (plural dru-wid-es), which was later altered to daru-wid- (based on the Celtic word for "oak tree") or could come from do-are-wid- ("who sees beyond").
All these forms are believed to come from a Proto-Celtic noun dru-wid-s (plural dru-wid-es). The second part of the word is thought to come from the Proto-Indo-European (PIE) verb weyd- ("to see or know"). The first part of the word has been debated by scholars. Most believe it comes from the PIE word derw- (similar to *dru-) meaning "oak tree," which also meant "strong or firm." This led to interpretations such as "oak-knower," "someone who knows trees," or "a priest with strong insight." This connection was noted by the Roman writer Pliny in the 1st century, who compared it to the Greek word "drŷs" ("oak"). Some scholars, however, suggest the first part might be an intensive prefix, meaning "very wise."
Practices and doctrines
Ancient and medieval writers provide information about the religious duties and social roles of druids in Celtic society. Greco-Roman and Irish sources agree that druids held important positions in pagan Celtic life. Julius Caesar wrote that druids were among the two most influential groups in the region, along with the nobles, and were responsible for organizing religious ceremonies, sacrifices, 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 had the power to exclude people from religious events, making them socially isolated. Other writers, such as Diodorus Siculus and Strabo, described druids as highly respected figures who could even stop battles if they intervened between opposing armies.
Diodorus Siculus called druids "philosophers" and "learned men in religious matters," while Strabo wrote that their knowledge included natural and moral philosophy. Ammianus Marcellinus described them as people who studied "obscure and profound subjects." Pomponius Mela was the first to mention that druid education was secret and took place in caves and forests. Cicero reported that a Gaulish druid claimed to understand nature in a way similar to Greek "physiologia" and used methods like augury and guessing to make predictions.
Druidic knowledge was passed down through memorized verses, and Caesar noted that it could take up to 20 years to complete their training. However, no ancient druidic verses have been confirmed to survive today. While instruction was oral, the Gauls used a written language based on Greek letters, which later shifted to Latin script. Caesar believed that druids avoided writing to protect their knowledge and improve memory. He wrote that many young men chose to study with druids, either by personal choice or because families sent them.
Greek and Roman writers often described druids as practicing human sacrifice. Caesar wrote that criminals were preferred as sacrificial victims, but if criminals were unavailable, innocent people could be used. One method involved burning victims alive inside a large wooden structure, now called a wicker man. A 10th-century text, the Commenta Bernensia, described sacrifices to gods like Teutates, Esus, and Taranis as drowning, hanging, and burning, respectively. Diodorus Siculus stated that druids acted as intermediaries between people and gods, using animal sacrifices and observing the movements of birds to predict the future. He also described a ritual where a human victim was stabbed, and the way their body reacted was used to interpret the future.
Archaeological findings, such as mass graves in Gaul, have been linked to human sacrifice, though some historians debate this. Jean-Louis Brunaux believed the graves were sites of sacrifice to a war god, while Martin Brown suggested they might be burials of honored warriors. Some scholars question whether Roman and Greek writers accurately described druids, noting that these cultures sometimes portrayed foreign groups as "barbaric" to highlight their own cultural superiority. Nora Chadwick, an expert on medieval literature, argued that accusations of druidic human sacrifice may have been Roman propaganda.
Ancient writers also described druidic beliefs. Alexander Cornelius Polyhistor called druids "philosophers" and noted their belief in the immortality of the soul and reincarnation, which he compared to Pythagorean teachings. Caesar wrote that druids taught that the soul moves to a new body after death, a belief he believed helped people face death bravely. He also mentioned that druids studied topics like the stars, geography, and natural philosophy. Diodorus Siculus, writing in 36 BCE, confirmed that druids followed the Pythagorean idea of soul immortality and reincarnation. Caesar also mentioned that druids believed the ancestor of a tribe was a god they called "Dispater," meaning "Father Dis." Diogenes Laertius, writing in the 3rd century CE, noted that druids used riddles and cryptic sayings to teach respect for the gods, discourage wrongdoing, and promote strong, honorable behavior.
Druids in mythology
Druids are important figures in Irish stories, often serving as high-ranking priests and advisors to kings and lords. They are known for their ability to predict the future and use special powers. 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 skill in predicting what will happen. In the tale of Deirdre of the Sorrows, a major 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 many people would be hurt because of her, and that Ulster’s three greatest warriors would be forced to leave their home for her sake. The king ignored this warning, but the prophecy came true.
Another famous druid is 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. As the Milesians approached, the druids of the Tuatha Dé Danann created a magical storm to stop their ships from landing. Amergin then called upon the spirit of Ireland itself, reciting a powerful chant known as The Song of Amergin. After successfully landing, he helped his royal brothers divide the land during their conquest of Ireland. For his actions, he was given the title Chief Ollam of Ireland.
Other druids from Irish myths include Tadg mac Nuadat, who appears in 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 often had important cultural and religious roles similar to those of male druids. 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 in the Fenian Cycle and a caretaker of Fionn mac Cumhaill during his childhood. 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 named Biróg, from the Tuatha Dé Danann, plays a key role in a folktale. In this story, the Fomorian warrior Balor tries to stop a prophecy that says he will be killed by his grandson. To do this, he imprisons his daughter Eithne on Tory Island to keep her away from men. Bé Chuille, the daughter of the woodland goddess Flidais, appears in a tale from the Metrical Dindshenchas. She joins three other Tuatha Dé members to defeat the evil Greek witch Carman. Other bandrúi include Relbeo, a Nemedian druid from The Book of Invasions, who is described as the daughter of the king of Greece and the mother of Fergus Lethderg and Alma One-Tooth. Dornoll, a bandrúi in Scotland, trained heroes like Laegaire and Conall in warfare. She was the daughter of Domnall Mildemail.
Classical writers, such as the Greek geographer Artemidorus Ephesius and the historian Strabo, mentioned the Gallizenae (or Gallisenae), who were virgin priestesses on the Île de Sein, near Pointe du Raz in western Brittany. Strabo wrote that the island was forbidden to men, but the women visited the mainland to meet their husbands. It is unknown which deities they honored. According to Pomponius Mela, the Gallizenae served as advisors and healers. He described them as nine priestesses who could control the sea and wind through incantations, change into animal forms, cure diseases, and predict the future. They only helped travelers who sought their guidance.
The Historia Augusta mentions that Alexander Severus received a prophecy about his death from a Gallic druidess (druiada). The same work records Aurelian asking druidesses about the fate of his descendants, and they predicted that Claudius II would succeed him. Flavius Vopiscus also noted that 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 Classical 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 governance, a view called "primitivism."
Historian Nora Chadwick, whose ideas were later used by Piggott, divided Classical descriptions of druids into two groups. The first, called the "Posidonian" tradition after the writer Posidonius, criticized Iron Age societies in Western Europe, calling them "barbaric." The second, called the "Alexandrian" group, focused on the scholarly traditions of Alexandria, Egypt, and showed more respect for these cultures. Piggott linked this to ideas called "hard primitivism" and "soft primitivism" studied by historians Arthur Oncken Lovejoy and Franz Boas.
Some scholars believe all Classical accounts of druids are unreliable or fictional. They argue that druids may have been invented by Roman writers to portray non-Roman societies as "barbaric," justifying Roman expansion into those regions.
The earliest surviving records of druids appear in two Greek texts from around 300 BCE: a philosophical history by Sotion of Alexandria and a study of magic attributed to Aristotle. These texts are lost, but they were quoted in a 2nd-century CE work called Vitae by Diogenes Laërtius. One passage mentions that some ancient Greek philosophers believed the study of philosophy began with "barbarians," including groups like the Magi in Persia, the Chaldaei in Babylon, the Gymnosophistae in India, and the druids among the Celts and Gauls, as noted by Aristotle and Sotion.
Greek and Roman texts from the 3rd century BCE refer to "barbarian philosophers," possibly describing the Gaulish druids.
The first detailed surviving 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 responsible for religious practices, sacrifices, and interpreting rituals. He said they were one of two respected classes in Gaul, alongside the equites (a privileged Roman class). They acted as judges and followed a leader chosen by vote or conflict. Disputes were settled annually at a sacred site in the Carnutes’ territory, considered the center of Gaul. Caesar claimed Britain was the heart of druidic learning and that druids were not found among German tribes east of the Rhine. Young men trained for years to become druids, memorizing religious teachings. They believed souls passed from one body to another and studied astronomy, theology, and the cosmos. Caesar also wrote that druids supervised human sacrifices, often using criminals burned in wicker effigies.
Modern historians have criticized Caesar’s account as inaccurate. Some, like Fustel de Coulanges, noted Caesar never mentioned druids in his accounts of conquering Gaul, nor did Aulus Hirtius, who continued his writings. Historian Ronald Hutton argued Caesar portrayed druids as both civilized (learned and pious) and barbaric (practicing human sacrifice) to justify Roman rule. Others, like Sean Dunham, suggested Caesar compared druids to Roman senators. Daphne Nash believed Caesar exaggerated druidic leadership and their ties to Britain.
Other historians think 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 Gaul’s political changes. John Creighton noted druidic influence in Britain may have declined by the mid-1st century BCE. Miranda Aldhouse-Green (2010) argued Caesar’s writings are the most reliable source on druids, as other Roman officials would have challenged false claims.
Other classical writers also wrote about druids. Cicero, a contemporary of Caesar, met a Gallic druid named Divitiacus of the Aedui tribe, who practiced augury. However, Caesar referred to him as "Diviciacus" and never called him a druid, instead presenting him as a political leader. Diodorus Siculus, writing in 36 BCE, described druids (called "drouidas") as philosophers and theologians, noting their roles alongside poets and singers.
Archaeology
As historian Jane Webster explained, "individual druids … are unlikely to be identified through archaeological evidence." A. P. Fitzpatrick studied what he thought were symbols related to the stars on late Iron Age swords. He found it difficult to connect any physical objects, even the Coligny calendar, to druidic culture.
Some archaeologists have tried to connect discoveries with written descriptions of druids. Anne Ross linked evidence of human sacrifice in Celtic society, such as the Lindow Man bog body, to Roman and Greek writings about druids overseeing such rituals. Miranda Aldhouse-Green, a professor 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. A 1996 discovery of a skeleton buried with advanced medical tools and possibly religious items was later 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 unique headband. The headband was too thin to be part of a leather helmet. It was made of bronze, with a wide band around the head and a thin strip crossing the top. Hair left on the metal shows it was worn directly on the head without padding. The headdress resembles images of priests from later Romano-British times, leading some archaeologists to suggest the man might have been a religious official, possibly a druid.
History of reception
During the Gallic Wars from 58 to 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 time describe how the new Roman rulers took steps to remove the druids from Gaul. Pliny the Elder, writing in the 70s CE, noted that 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, wrote that Emperor Augustus (ruled 27 BCE–14 CE) made it illegal for someone to be both a druid and a Roman citizen. Later, Emperor Claudius (ruled 41–54 CE) passed a law that "thoroughly suppressed" druids by banning their religious practices.
The strongest evidence of druidic traditions in the British Isles comes from the Celtic word druwid-, which appears in Old Irish as druídecht (meaning "magic") and in Welsh as dryw (meaning "seer"). After the Christianization of Wales, which was complete by the 7th century, the druids as a priestly group no longer existed. However, roles like the bard and the "seer" (Welsh: dryw) continued in medieval Wales until the 13th century.
In 1764, Minister Macauley reported finding five druidic altars, including a large circle of stones near Stallir House on Boreray, near the westernmost settlement of the UK, St. Kilda.
Classics professor Phillip Freeman discussed references to "dryades," which he translated as "druidesses," in a 4th-century CE collection of imperial biographies called the Historia Augusta. These passages describe Gaulish women called "dryades" and suggest that some druidic traditions, like prophecy, survived among native people in Roman Gaul. Female druids also appear 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.
The story of Vortigern, as told by Nennius, is one of the few accounts of druids possibly surviving in Britain after the Romans arrived. Vortigern invited twelve druids to help him after being excommunicated by Germanus of Auxerre.
In stories about saints and martyrs, druids are often shown 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. They try to stop Saint Patrick and Saint Columba by creating clouds and mist. Before the battle of Culdremne in 561 CE, a druid created an unclear protective barrier around one of the armies. Irish druids had a unique style of cutting their hair, and the word druí was used to describe the Latin word magus (meaning "magician"). In one passage, Saint Columba refers to Jesus as his druid. A life of Saint Beuno mentions that when he died, he saw "all the saints and druids" in a vision.
In the Life of Martin of Tours by Sulpicius Severus, Martin mistakes a peasant funeral for a druidic sacrifice. He stops the procession by raising his cross, causing the people to freeze and whirl in confusion. After realizing his mistake, Martin lets them continue.
In 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 to druids. William Stukeley (1687–1765) later popularized this idea. John Toland (1670–1722) is wrongly credited with founding the Ancient Druid Order (ADO), but historian Ronald Hutton found that the ADO was actually created in 1909 by George Watson MacGregor Reid. The ADO 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. The role of bards in 10th-century Wales was established by Hywel Dda, and the idea that druids were their predecessors arose in the 18th century.
In the 19th century, some people wrongly believed, based on the Gallic Wars, that druids were the main group resisting the Romans in Gaul. This idea was later disproven but still appears in folk history.
Druids became more common in popular culture during the Romanticism movement. In 1809, French author Chateaubriand wrote a novel about a druid priestess and a Roman soldier. Opera also featured druids, such as Giovanni Pacini’s La Sacerdotessa d'Irminsul (1817) and Vincenzo Bellini’s Norma (1831). The story of Norma was inspired by earlier works and resembles the tale of Medea. The moon goddess in Norma is addressed in a famous aria.
A key figure in the 19th-century revival of druidic ideas was Welshman Edward Williams, known as Iolo Morganwg. His writings, published after his death, are not seen as credible by modern scholars. Williams claimed he collected ancient knowledge from a group called the "Gorsedd of Bards of the Isles of Britain." His works, such as The Iolo Manuscripts (1849) and Barddas (1862), are not considered reliable historical sources.