Ancient Celtic Religion & Beliefs

Ancient Greek and Roman writers, such as Julius Caesar, Strabo, and Tacitus, provided descriptions of the Celts and their practices. While invaluable, these accounts are often limited in scope and may be biased, as they were written from the perspective of outsiders, sometimes even enemies. Archaeological findings, including artefacts, inscriptions, and sacred sites, offer additional significant insights. Objects like the Gundestrup Cauldron, Celtic coins, and statues, as well as sacred sites like Stonehenge and the Hill of Tara, help us understand the religious symbolism and practices of the Celts.

The Celts were Polytheistic

Celtic tradition and stories are full of gods and goddesses. However, unlike in Greece and Rome, Irish gods and goddesses did not have clear functions. It seems that at different times in different stories, different gods have responsibility for a single aspect of human life or of a part of nature.

When the Romans write about Celtic beliefs, there is great confusion. For example, when they looked for the equivalent god of War, Mars, among the Celtic gods, they found 69 or more. It seems that many gods had responsibility for war in Celtic beliefs, depending on the circumstances.

They worship as their divinity, Mercury in particular, and have many images of him, and regard him as the inventor of all arts, they consider him the guide of their journeys and marches, and believe him to have great influence over the acquisition of gain and mercantile transactions. Next to him they worship Apollo, and Mars, and Jupiter, and Minerva; respecting these deities they have for the most part the same belief as other nations: that Apollo averts diseases, that Minerva imparts the invention of manufactures, that Jupiter possesses the sovereignty of the heavenly powers; that Mars presides over wars. To him, when they have determined to engage in battle, they commonly vow those things which they shall take in war. When they have conquered, they sacrifice whatever captured animals may have survived the conflict, and collect the other things into one place. In many states you may see piles of these things heaped up in their consecrated spots; nor does it often happen that any one, disregarding the sanctity of the case, dares either to secrete in his house things captured, or take away those deposited; and the most severe punishment, with torture, has been established for such a deed.

Julius Caesar, The Gallic Wars, Book 6, Chapter 17

The names of over two hundred Celtic deities have survived, although it is likely that many of these were alternative names, regional names or titles for the same deity. Some deities were venerated only in one region, but others were more widely known.

The Celts Practised both Animal and Human Sacrifice

In many ancient religions and in some areas of the world today, the giving up of a life, either animal or human, can be considered ‘desirable’ by the gods. For pre-Christian Celts, when they made a sacrifice, it had to be destroyed in order for it to be passed over to the gods. For this reason animals had to be killed and offerings of any objects destroyed.

Human sacrifice of slaves and enemies among Celts in Europe did happen but it was not common. A druid would stab the victim and interpret the process of the unfortunate person’s death. It’s less certain whether human sacrifice was part of the Irish Celtic religion.

The whole nation of the Gauls is greatly devoted to ritual observances, and for that reason those who are smitten with the more grievous maladies and who are engaged in the perils of battle either sacrifice human victims or vow to do so, employing the Druids as ministers for such sacrifices. They believe, in effect, that, unless for a man’s life a man’s life be paid, the majesty of the immortal gods may not be appeased; and in public, as in private, life they observe an ordinance of sacrifices of the same kind. Others use figures of immense size, whose limbs, woven out of twigs, they fill with living men and set on fire, and the men perish in a sheet of flame. They believe that the execution of those who have been caught in the act of theft or robbery or some crime is more pleasing to the immortal gods; but when the supply of such fails they resort to the execution even of the innocent.

Julius Ceasur, Gallic War Book6, Chapter 16

Why did the Celts make sacrifices? According to Celtic tradition, they did so in the hope of receiving good luck or other favours. In order to ward off the bad or evil side of the spiritual world, it was necessary to pacify the gods with gifts.

Literary evidence of Celts sacrificing humans

We have writings from two Classical authors.

The Romans put a stop both to these customs and to the ones connected with sacrifice and divination, as they were in conflict with our own ways: for example, they would strike a man who had been consecrated for sacrifice in the back with a sword, and make prophecies based on his death-spasms; and they would not sacrifice without the presence of the Druids. Other kinds of human sacrifices have been reported as well: some men they would shoot dead with arrows and impale in the temples; or they would construct a huge figure of straw and wood, and having thrown cattle and all manner of wild animals and humans into it, they would make a burnt offering of the whole thing (trans. by Benjamin Fortson, in Koch and Carey 1995, 18).

Strabo, Geography (4.1.13)

All the people of Gaul are completely devoted to religion, and for this reason those who are greatly affected by diseases and in the dangers of battle either sacrifice human victims or vow to do so using the Druids as administrators to these sacrifices, since it is judged that unless for a man’s life a man’s life is given back, the will of the immortal gods cannot be placated. In public affairs they have instituted the same kind of sacrifice. Others have effigies of great size interwoven with twigs, the limbs of which are filled up with living people which are set on fire from below, and the people are deprived of life surrounded by flames. It is judged that the punishment of those who participated in theft or brigandage or other crimes are more pleasing to the immortal gods; but when the supplies of this kind fail, they even go so low as to inflict punishment on the innocent (trans. Anne Lea, in Koch and Carey 1995. 22).

Julius Caesar, De Bello Gallico 6.16

Archaeological evidence of Celts sacrificing humans

The best archaeological data supporting Celtic human sacrifice is from bodies dug out of bogs.

Of these bodies, the most famous, Cashel Man was discovered near Portlaoise in 2011, and at over 4000 years old, is said to be the oldest European bog body ever found with skin intact; then there is Old Croghan Man from Co. Offaly, and Clonycavan Man from Co. Meath.

At 6’6″, Old Croghan Man, who was killed between 362 BC and 175 BC, was a giant of a man. He bore the appearance of a nobleman from his well-manicured soft hands to his diet, rich in meat. Clonycavan Man was little more than 5 ft and used pine resin to keep his hair in place, probably sourced from Spain (a precursor to hair gel!) and demonstrates that he was a person of some wealth and standing in the community.

Lindow man was almost certainly a ritual sacrifice; he was strangled, hit on the head, and had his throat cut, in quick order, then surrendered to the bog. This pattern fits the “three-fold” death referred to in medieval Irish tales. What’s more, the man seems to have been of high social rank, and a willing victim.

The Celts believed in the immortality of the soul

It seems that the Celts believed in life after death, but there is little to show how they thought that this could be achieved. In fact, there is little in the way of ethics in Celtic religion. Prior to the arrival of Christianity, the concept of punishment by the gods for ‘behaving badly’ did not seem to exist. It appears as if the gods were not interested in ‘good or evil’.

Literary references of Celts belief in life after death

The Pythagorean doctrine prevails among them (the Gauls), teaching that the souls of men are immortal and live again for a fixed number of years inhabited in another body.

Diodorus Siculus, Bibliotheca Historica Book V, 28, 6

..And yet, they have both their own eloquence and their own teachers of wisdom, the Druids.

One of the precepts they teach — obviously to make them better for war — has leaked into common knowledge, namely, that their souls are eternal and that there is a second life for the dead. Therefore they cremate and bury with the dead things that are suitable for the living. Long ago, traders’ accounts and debt collection were deferred until they died, and some individuals happily threw themselves onto the pyres of their loved ones as if they were going to live with them!

Pomponius Mela, De chorographia  3.19

References to life after death in Celtic Mythology

Many of the tales in Welsh and Irish mythology show people being reincarnated in one way or another, often through a series of transformations into several different kinds of animals before arriving in human form again.

Welsh mythology has a number of references to reincarnation. Taliesin, a legendary bard who possesses otherworldly knowledge, including the ability to see into the distant past, as well as the ability to see into former incarnations. In somewhat enigmatic fashion, in the tale of Cad Goddau, he states that he existed before the world began. Throughout this tale, he gives testimony to the various shapes and guises that he has taken with respects to his previous existences. In Math Fab Mathonwy Gwydion and his brother Gilfaethwy are punished and made to take the forms of mating deer, pigs, and wolves. Afterward, they are allowed to resume their previous forms. While these transformations may simply appear to be shapeshifting events, it is possible that they are allegories for transmigration of the soul.

Irish lore has similar references to reincarnation. In the tale of Scel Tuain Meic Cairill, we find a man who lived in various forms of beasts for hundreds of years. With each incarnation as a new animal, he becomes young once again. In The Cattle Raid of Cooley, the two cattle that are the central focus of the story have a whole host of previous incarnations as various animals. These include: Stags, Ravens, Worms, Warriors, etc.

Archaeological evidence to suggest Celtic belief in life after death

Although the Celts had a variety of different kinds of burial practices – cremation, burial, and a process known as excarnation, or ‘sky burials’, where the body was left out in the open until the flesh had been picked off by birds, leaving the bones clean.

When they were buried, they often had grave-goods, like rings, beads, daggers, joints of meat (pork, usually), and gaming dice, buried with them. An example of the latter is a 1st-century BCE burial chamber in Welwyn Garden City burial in Hertfordshire in southeast England where the deceased was cremated while wrapped in a bearskin. The remains were then deposited in a chamber along with paraphernalia for drinking and feasting, including five large Roman amphorae. The inclusion of 24 exquisitely-made glass gaming pieces shows the importance of recreation in a society where leisure may have been associated with elite status. 

Celtic Religion was strong on communal and ritual celebration

When sacrifices were made, elaborate feasting on sacrificed animals provided a communal link with the supernatural world.

A good example of ritual religious practice is the Bull Feast (known as Tarbhfhess in Gaelic). This was the Celtic means of choosing a King, especially the King of Tara. A bull was sacrificed and a chosen man drank the blood and ate its meat. He would then go to sleep to the incantations of 4 druids (Celtic priests) and have revealed to him in a dream who should be the rightful king. This was only part of the election process but it shows the importance put on gaining the approval of the gods.

Celtic beliefs involved a variety of supernatural beings

It seems that the early Celts believed in lots of supernatural beings who occupied and controlled parts of the natural world. This gave rise, for example, to lots of Celtic legends about fairies.

The Celts believed that the world was alive

Part of Irish Celtic religion was the belief that naturally occurring things such as rocks, rivers and trees had spirits. These were not necessarily good or bad spirits but could react in a certain way, depending on how they were treated.