Ireland's creatures come from two places: the medieval manuscripts, which give us the Fomorians and the great animals of the old tales, and the folklore of the last few centuries, which gave us the banshee, the púca, the dullahan and the leprechaun. This guide sorts them by kind and says where each one comes from.
| Creature | What it is | Comes from |
|---|---|---|
| Banshee | A spirit whose keening foretells a death | Folklore |
| Dullahan | A headless rider who carries his own head | Folklore |
| Sluagh | A host of restless dead on the night wind | Irish and Scottish Gaelic folklore |
| Púca | A shape-shifting trickster, often a black horse | Folklore |
| Cat Sídhe | A fairy cat said to steal souls | Folk belief, strongest in Scottish Gaelic tradition |
| Leprechaun | A solitary fairy cobbler guarding gold | Folklore |
| Merrow | The Irish mermaid or merman | Folklore, recorded by nineteenth-century collectors |
| Fomorians | Hostile sea-linked beings and giants | Medieval Mythological Cycle |
Three of Ireland's best-known beings are bound up with death, but they behave very differently.
The banshee (bean sídhe, "woman of the sídhe") is the figure most people think of first. Her keening, the caoineadh, is the same word used for the wail of human mourners at a wake, and tradition says she attends certain old Gaelic families, including the O'Neills, O'Briens, O'Connors and O'Gradys. She is described in several ways: a young woman in white or grey, an old woman in a grey cloak, or a "washer at the ford" seen cleaning bloodstained clothes in a stream, which is itself an ill omen. She is a herald, not a killer.
The dullahan is a different matter. He is a headless rider on a black horse, or the driver of the black coach called the Cóiste Bodhar, who carries his own severed head, with its darting eyes and wide grin, and wherever he stops someone is said to die. Tradition says he fears gold, so a gold pin or coin once protected travellers. He is often paired with the banshee as a death omen, though he is treated as the more dangerous to meet. Many people connect him with the headless horseman of Washington Irving's The Legend of Sleepy Hollow.
The Sluagh (Sluagh na Marbh, "host of the dead") are not a single spirit but a crowd of unforgiven souls said to fly through the night from the west. Unlike a banshee, which heralds one family's death, they act as a group and were feared for seizing the living or carrying off the souls of the dying. In Highland tradition, households kept west-facing windows shut at night to keep the host out.
The púca is most often seen as a black horse, though it can also take the form of a goat, rabbit or dog. It can be helpful or harmful, giving an unwary traveller a terrifying ride or, in gentler tellings, doing farm work overnight. It is tied to Samhain: in some regions a share of the harvest was left for it, and blackberries were not picked after 1 November because the púca was said to have spoiled them. Place-names keep it too, since Poulaphouca in County Wicklow comes from Poll an Phúca, "the púca's hole". Its name is probably related to the English Puck, though the details are disputed.
The cat sídhe is a fairy cat about the size of a dog, with dark fur and a pale patch on its breast. People kept watch over the dead because it was said to steal a corpse's soul if it reached the body before burial, and at Samhain a saucer of milk was thought to win its goodwill. The name is most closely linked with Scottish Gaelic tradition, where it is the cat sìth, though Irish and Manx folklore have similar stories.
Stingy Jack is a human trickster rather than a creature, but he belongs in the same company. He outwits the Devil twice, and when he dies neither Heaven nor Hell will take him, so he wanders with a single burning coal in a hollowed-out turnip. That is the origin story of the jack-o'-lantern; Irish and Scottish people carved turnips and potatoes at Samhain, and emigrants later switched to pumpkins in North America.
The leprechaun works alone, unlike the "trooping fairies" that live in groups. He mends and makes shoes for the other sídhe folk, and his gold is explained as payment gathered over a very long life. A human who catches one can force him to reveal the hoard, but he rarely keeps his side of the bargain. The green suit is a later invention.
The merrow (murúch, "sea maiden") lives under the waves but can come ashore by taking off a magic cap, the cohuleen druith, which also lets her travel underwater. Female merrows are described as beautiful, with green hair and fish tails, and males as far less attractive. A common tale has a fisherman hide the cap so that a merrow wife stays on land, until she finds it and returns to the sea. It closely resembles the selkie legends of Scotland and Orkney, and the red-cap detail comes from the nineteenth-century collections of Thomas Crofton Croker.
The one great monstrous people in the medieval texts are the Fomorians (Fomoire), hostile otherworldly beings linked with the sea and with chaos. Medieval writers describe them in two ways, as northern sea-raiders in some places and as monstrous giants beneath the waves or in the Otherworld in others. Their role is not purely villainous, because the Fomorians and the Tuatha Dé Danann intermarried and made alliances, and the conflict is often read as order against the forces that threaten culture and craft. Their king, Balor, is killed by his grandson Lugh at the Second Battle of Moytura, told in Cath Maige Tuired, which ends Fomorian dominance. Read more under the Mythological Cycle.
In the manuscript tales animals are often central to the plot and not just scenery. The Children of Lir are turned into swans by their jealous stepmother and spend nine hundred years in that form. Étaín is transformed again and again, ending as a fly that is swallowed and reborn. The whole Táin Bó Cúailnge turns on a cattle raid for a famous brown bull. And the hero Cú Chulainn takes his name, "hound of Culann", from a guard dog he killed as a boy and then replaced. Salmon, horses and deer play similar parts in the Fenian Cycle, where Fionn gains wisdom from a salmon.
A note on sources. The folklore creatures above rest on oral tradition and on nineteenth- and twentieth-century collections, not on a single medieval text, so details differ from county to county. Where the entries say a point is disputed, this guide says so too.
Browse every being on the creatures page, read how they fit into the festival calendar in the Samhain guide, or start from the beginner's guide to Irish mythology.
The best known are the banshee, the leprechaun, the púca, the dullahan and the merrow, which come from folklore, and the Fomorians, who come from the medieval Mythological Cycle. The two groups are different in kind: the folklore beings survive mainly through oral tradition and later collections, while the Fomorians appear in written medieval texts such as Cath Maige Tuired.
Mythology here means the stories in medieval manuscripts, such as the Mythological, Ulster and Fenian Cycles. Folklore means beliefs and tales kept in oral tradition and written down mostly in the nineteenth and twentieth centuries. Most of the famous creatures, including the banshee, púca and leprechaun, belong to folklore and have no single medieval source text.
Not in the usual sense. The banshee (bean sídhe, "woman of the sídhe") is a spirit whose keening is said to foretell a death in certain old Gaelic families. She is a warning and a mourner, not an attacker. The dullahan and the Sluagh are the ones tradition treats as dangerous to meet.
The traditional leprechaun is a small, elderly lone cobbler in a leather apron who guards a hoard of gold. The bright green suit is a nineteenth- and twentieth-century addition. The name probably comes from the Old Irish luchorpán, "small body".
Yes, in two ways. Folklore beings often take animal shapes, such as the púca as a black horse or the cat sídhe as a large dark cat. In the old stories animals are central to the plot: the Children of Lir become swans, Étaín is reborn after being transformed, and a quarrel over two bulls drives the Táin Bó Cúailnge.
The púca, the cat sídhe, the Sluagh and Stingy Jack are all tied to Samhain in tradition, when the boundary with the Otherworld was thought to be thinnest. The Samhain guide covers the customs that grew up around them.