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Celtic Mythology – An Overview of a Unique Mythology

Celtic mythology is one of the oldest, most unique, and yet least well-known of all ancient European mythologies. Compared to Greek, Roman or Norse mythology, not many people know about Celtic myth.

At one time, the many different Celtic tribes covered all of Europe in the Iron age – from Spain and Portugal to modern-day Turkey, as well as Britain and Ireland. They were never unified, however, and so neither was their culture and mythology. Different Celtic tribes had their own variations of the base Celtic gods, myths, and mythological creatures. Eventually, most Celts fell to the Roman Empire one by one.

Today, some of that lost Celtic mythology is preserved from archeological evidence and from some written Roman sources. The chief source of our knowledge about Celtic mythology, however, are the still-living myths of Ireland, Scotland, Wales, Britain, and Brittany (North-Western France). Irish mythology, in particular, is viewed as the most direct and authentic ancestor of the old Celtic myths.

Who Were the Celts?

The ancient Celts were neither a single race nor an ethnicity or a country. Instead, they were a large assortment of different tribes all over Europe that were united by common (or rather – similar) language, culture, and mythology. Even though they never unified in a single kingdom, their culture was highly influential for the whole continent for centuries after the Celts’ demise.

Where Did They Come From?

Originally, the Celts came from central Europe and started spreading across the continent around 1,000 BC, long before the rise of both Rome and the various Germanic tribes.

The expansion of the Celts happened not just by conquest but also by cultural integration – as they traveled in bands across Europe, they interacted with other tribes and peoples and shared their language, culture, and mythology.

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Gauls asterix
The Gauls as depicted in the famous comic series Asterix the Gaul

Eventually, around 225 BC, their civilization had reached as far as Spain in the west, Turkey in the east, and Britain and Ireland in the north. One of the most famous Celtic tribes today, for example, were the Gauls in modern-day France.

Celtic Culture and Society

Stonehenge Celts
Stonehenge was used by the Celtic Druids to hold ceremonies

The basic structure of Celtic society was simple and effective. Each tribe or small kingdom was composed of three castes – nobility, druids, and commoners. The commoner caste was self-explanatory – it included all farmers and workers performing manual jobs. The nobility caste included not just the ruler and their family but the warriors of each tribe as well.

The Celtic druids were arguably the most unique and fascinating group. They functioned as the tribe’s religious leaders, teachers, advisors, judges, and so on. In short, they performed all higher-level jobs in a society and were responsible for preserving and developing Celtic culture and mythology.

The Fall of The Celts

The disorganization of the various Celtic tribes was ultimately their downfall. As the Roman Empire kept developing its strict and organized society and military, no individual Celtic tribe or small kingdom was strong enough to withstand it. The rise of the Germanic tribes in Central Europe also escalated the fall of Celtic culture.

After several centuries of cultural domination across the continent, the Celts started falling one by one. Eventually, in the first century AD, the Roman Empire had subdued almost all Celtic tribes across Europe, including in most of Britain. The only surviving independent Celtic tribes at the time could be found in Ireland and in Northern Britain, i.e., today’s Scotland. 

The Six Celtic Tribes That Have Survived to This Day

Six countries and regions today pride themselves for being the direct descendants of the ancient Celts. Those include:

  • Ireland and Northern Ireland
  • The Isle of Man (a small island between England and Ireland)
  • Scotland
  • Wales
  • Cornwall (south-western England)
  • Britanny (north-western France)

Of those, the Irish are typically viewed as the “purest” descendants of the Celts, as Britain and France have been invaded, conquered by, and have interacted with various other cultures since then, including but not limited to the Romans, Saxons, Norse, Franks, Normans, and others. Even with all that cultural intermingling, many Celtic myths are preserved in Britain and in Britanny but Irish mythology remains the clearest indication of what the ancient Celtic mythology looked like.

The Various Celtic Deities

Most Celtic gods were local deities as almost every tribe of Celts had its own patron god they worshipped. Similar to the ancient Greeks, even when a larger Celtic tribe or kingdom recognized multiple gods, they still worshipped one above all others. That one deity wasn’t necessarily the “main” deity of the Celtic pantheon – it could be any one god native to the region or connected to the culture.

It was also common for different Celtic tribes to have different names for the same deities. We know that not just from what’s been preserved in the six surviving Celtic cultures but also from archeological evidence and Roman writings.

The latter are particularly curious because the Romans typically substituted the names of the Celtic deities with those of their Roman counterparts. For example, the chief Celtic god Dagda was called Jupiter in Julius Ceaser’s writings about his war with the Gauls. Similarly, the Celtic god of war Neit was called Mars, the goddess Brigit was called Minerva, Lugh was called Apollo, and so on.

The Roman writers likely did this for convenience’s sake as well as an attempt to “Romanize” Celtic culture. The very cornerstone of the Roman Empire was their ability to quickly integrate all cultures they conquered into their society so they didn’t hesitate outright erase entire cultures by just translating their names and myths in Latin and into Roman mythology.

The upsides to that were that Roman mythology itself was getting richer and richer with each conquest and that contemporary historians are able to learn a lot about the conquered cultures by simply studying Roman mythology.

All in all, we now know of several dozen Celtic deities and many myths, supernatural creatures, as well as various historic and semi-historic Celtic kings and heroes. Of all the Celtic deities we know of today the most famous ones include:

  • Dagda, the leader of the gods
  • Morrigan, the trinity goddess of war
  • Lugh, the warrior god of kingship and law
  • Brigid, the goddess of wisdom and poetry
  • Ériu, the goddess of horses and the Celtic summer festival
  • Nodens, the god of hunting and the sea
  • Dian Cécht, the Irish god of healing

The variations of these and the other Celtic gods can be seen in the multiple Celtic mythological cycles preserved to this day.

Celtic Gaelic Mythology

Gaelic mythology is the Celtic mythology that’s been recorded in Ireland and Scotland – arguably the two regions where Celtic culture and mythology have remained most preserved.

The Irish Celtic/Gaelic mythology generally consists of four cycles, while Scottish Celtic/Gaelic mythology is mostly collected in the Hebridean mythology and folklore stories.

1. The Mythological Cycle

The Mythological Cycle of Irish stories focuses on the myths and deeds of the Celtic gods that were popular in Ireland. It goes over the struggles of the five main races of gods and supernatural beings who fought for control over Ireland. The main protagonists of the Mythological Cycle are the Tuatha Dé Danann, the main deities of pre-Christian Gaelic Ireland, led by god Dagda.

2. The Ulster Cycle

The Ulster Cycle, also known as the Red Branch Cycle or Rúraíocht in Irish, recounts the deeds of various legendary Irish warriors and heroes. It mostly focuses on the Medieval period Ulaid kingdom in north-eastern Ireland. The hero featured most prominently in the Ulster Cycle sagas is Cuchulain, the most famous champion of Irish mythology.

3. The Historical Cycle / Cycle of the Kings

As its name implies, the Kings’ Cycle focuses on the many famous kings of Irish history and mythology. It goes over famous figures such as Guaire Aidne mac Colmáin, Diarmait mac Cerbaill,  Lugaid mac Con, Éogan Mór, Conall Corc, Cormac mac Airt, Brian Bóruma, Conn of the Hundred Battles, Lóegaire mac Néill, Crimthann mac Fidaig, Niall of the Nine Hostages, and others.

4. The Fenian Cycle

Also known as the Finn Cycle or the Ossianic Cycle after its narrator Oisín, the Fenian Cycle recounts the deeds of the mythical Irish hero Fionn mac Cumhaill or just Find, Finn or Fionn in Irish. In this cycle, Finn roams Ireland with his band of warriors called the Fianna. Some of the other famous members of the Fianna include Caílte, Diarmuid, Oisín’s son Oscar, and Fionn’s enemy Goll mac Morna.

Hebridean Mythology and Folklore

The Hebrides, both inner and outer, are a series of small islands off the coast of Scotland. Thanks to the isolation provided by the sea, these islands have managed to preserve a great deal of old Celtic myths and legends, safe from the Saxon, Nordic, Norman, and Christian influences that have washed over Britain over the centuries.

The Hebridean mythology and folklore focus mostly on tales and sagas about the sea, and various water-based Celtic legendary creatures such as the Kelpies, the blue men of the Minch, the Seonaidh water spirits, the Merpeople, as well as the various Loch monsters.

This cycle of sagas and stories also talks about other creatures such as werewolves, will-o’-the-wisp, fairies, and others.

Celtic Brythonic Mythology

Brythonic mythology is the second largest section of Celtic myths preserved today. These myths come from the Wales, English (Cornish), and Britanny regions, and are the basis of many of the most famous British legends today, including the myths of King Arthur and the knights of the round table. Most of the Arthurian myths were Christianized by Medieval monks but their origins were undoubtedly Celtic.

Welsh Celtic Mythology

As Celtic myths were generally recorded orally by the Celtic druids, most of them were lost or changed over time. That is both the beauty and tragedy of spoken myths – they evolve and blossom over time but many of them are left inaccessible in the future.

In the case of Welsh mythology, however, we do have some written Medieval sources of old Celtic myths, namely the White Book of Rhydderch, the Red Book of Hergest, the Book of Taliesin, and the Book of Aneirin. There are also some Latin historian works that shed light on Welsh mythology such as the Historia Brittonum  (History of the Britons), the Historia Regum Britanniae (History of the Kings of Britain), and some later folklore, such as the Welsh Fairy Book by William Jenkyn Thomas.

Many of the original myths of King Arthur are also contained in Welsh mythology. These include the tale of Culhwch and Olwen, the myth of Owain, or The Lady of the Fountain, the saga of Perceval, the Story of the Grail, the romance Geraint son of Erbin, the poem Preiddeu Annwfn, and others. There’s also the story of the Welsh magician Myrddin who later became Merlin in the story of King Arthur.

Cornish Celtic Mythology

King Arthur tintagel
Sculpture of King Arthur in Tintagel

The mythology of the Cornwall Celts in south-western England consists of many folk traditions recorded in that region as well as in other parts of England. This cycle includes various stories of mermaids, giants, pobel vean or little people, pixies and fairies, and others. These myths are the origins of some of the most famous British folk stories such as that of Jack, the Giant Killer.

Cornish mythology also claims to be the birthplace of the Arthurian myths as the mythic figure was said to be born in that region – in Tintagel, at the Atlantic coast. Another famous Arthurian story that comes from Cornish mythology is the romance of Tristan and Iseult.

Breton Celtic Mythology

This is the mythology of the people of the Britanny region in north-western France. These were folks who had migrated to France from the British islands in the third century AD. While they were already Christianized at the time, they had still preserved some of their old Celtic myths and legends and brought them (back to) France.

Most of the Breton Celtic myths are very similar to those of Wales and Cornwall and tell of various supernatural creatures, gods, and stories such as those of the Morgens water spirits, the Ankou servant of Death, the Korrigan dwarf-like spirit, and the Bugul Noz fairy.

Celtic Mythology in Modern Art and Culture

It’s virtually impossible to compile all the instances of Celtic influence in contemporary culture. Celtic mythology has seeped into almost every religion, mythology, and culture in Europe over the last 3,000 years – from the Roman and Germanic myths that were directly affected to the legends of most other cultures that came after them.

Christian myths and traditions were also strongly influenced by Celtic myths as the Medieval Christians often directly stole Celtic myths and incorporated them into their own mythos. The stories of King Arthur, the wizard Merlin, and the knights of the round table are the easiest examples.

Today, most fantasy literature, art, movies, music, and video games are as much influenced by Celtic mythology as they are by the Nordic myths and legends.

Wrapping Up

The advent of Christianity had a significant impact on Celtic culture from the 5th century onwards, as it slowly lost its relevance and eventually faded out of the mainstream. Today, Celtic mythology continues to be a fascinating subject, with much that is mysterious and unknown about it. While it’s not as well-known as other European mythologies, its impact on all subsequent cultures is undeniable.

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Yordan Zhelyazkov
Yordan Zhelyazkov

Yordan Zhelyazkov is a published fantasy author and an experienced copywriter. While he has degrees in both Creative Writing and Marketing, much of his research and work are focused on history and mythology. He’s been working in the field for years and has amassed a great deal of knowledge on Norse, Greek, Egyptian, Mesoamerican, Japanese mythology, and others.