The Mythological Cycle is a grouping of stories and poems from Irish mythology. These tales focus on the god-like Tuatha Dé Danann, who are inspired by Ireland's ancient pagan gods, as well as other mythical groups like the Fomorians and the Fir Bolg. It is one of four major story cycles in early Irish myths and legends, along with the Ulster Cycle, the Fianna Cycle, and the Cycles of the Kings. The term "Mythological Cycle" became commonly used around 1881–1883 by Arbois de Jubainville. James MacKillop notes that the term is now "somewhat awkward," and John T. Koch says it can be "potentially misleading," because the stories in this cycle only cover a small part of Irish mythology. He prefers the name "Cycle of the Gods" suggested by T Ó Cathasaigh. Important works in this cycle include the Lebor Gabála Érenn ("Book of Invasions"), the Cath Maige Tuired ("Battle of Moytura"), the Aided Chlainne Lir ("Children of Lir"), and the Tochmarc Étaíne ("The Wooing of Étaín").
Overview
The characters in these stories are mostly gods from Ireland’s pre-Christian past. However, some experts are careful to say they are only "godlike" beings, not actual gods. This is because the Christian writers who recorded these stories usually avoided calling the Tuatha Dé Danann and similar figures directly as deities. Even so, their divine nature is still clear in the writings, which show traces of ancient Irish beliefs in many gods.
Examples of these stories include prose tales, poems, and pseudo-historical records, such as Lebor Gabála Érenn (often called The Book of Invasions), found in old manuscripts. Some stories, like Cath Maige Tuired and The Fate of the Children of Tuireann, were written later and appear in paper manuscripts from nearly modern times.
Some later historical works, such as the Annals of the Four Masters and Geoffrey Keating’s History of Ireland (Foras Feasa ar Éirinn), are also sometimes used as sources. These texts include notes and rewritten versions of Lebor Gabála Érenn stories.
Oral folktales, such as those about Cian’s secret meeting with Balor’s daughter to retrieve the magical cow Glas Gaibhnenn, are also considered part of this cycle.
The gods from the invading groups are described as having lived on Earth and ruled Ireland before humans (like the Milesians). Later, the Tuatha Dé Danann are said to have hidden in the sídhe (fairy mounds) and used féth fiada (fairy mist) to stay hidden. Though they disappeared, they sometimes appear in other stories, such as Lugh’s role as a divine father or Morrígan’s rivalry with the hero Cú Chulainn. Other examples include encounters between characters like Finnian and fairy mound dwellers, or Cormac mac Airt and his grandfather visiting otherworldly realms.
Collections of literature, while not fully part of this cycle, still include small details about these deities.
Lists of literature
The table below shows a list of all the titles of myth stories that still exist and are available to read.
History of the Mythological Cycle
The main source of Irish mythology comes from a book called The Book of Invasions, or Lebor Gabala Erenn. This book is a shorter version of stories written in both prose and poetry about the origins of Ireland and its gods. The original version of the book was longer but was destroyed, likely during Viking attacks or during wartime.
Another important source is a book written by a chronicler named Keating in the 17th century. Keating used materials that had not been published before. Earlier chroniclers, Nennius and Eochaid Ua Flainn, who lived in the 10th century, recorded Irish mythology in poetry. Their writings are short and not very detailed, but they include valuable information about the spiritual beliefs of the time. The Tuatha De Danann, a group of gods in Irish mythology, share similarities with the gods of Greek mythology. The Greek gods were called "the Golden Race" by a writer named Hesiod, and the same kind of descriptions appear in stories about Celtic gods.
In Irish mythology, Ireland was invaded six times. The first five invasions were led by beings from otherworldly places, and the sixth was led by the Milesians. The Tuatha De Danann were said to have come from the heavens, but this might have been a mistake by scribes who did not know how to describe their origins. These scribes borrowed ideas from other ancient religions, like Greek, Roman, and Eastern myths, to create stories about the Tuatha De Danann’s origins. The Gauls, another group in mythology, were believed to have come from beneath the Earth. This idea was passed down by druids, who were priests in ancient times, and it was linked to Dispater, the god of the underworld.
At the time, Earth was thought of as a woman, so the idea of the Gauls coming from the Earth was seen as a metaphor, not a literal journey from hell. Druids also believed the Earth, moon, and sun were created, similar to stories told by Brahmans, religious leaders in ancient India. Like other myths, the Gauls believed that trees and mountains held up the sky.
These stories were passed down through spoken word because Ireland was not invaded during some periods, unlike other nearby countries. Druidic schools also wanted to keep the stories alive by sharing them verbally. This helped keep the stories part of Irish culture. When Christian scribes arrived in Ireland, they wrote the stories in Latin. Over time, many of these texts were lost or destroyed during Viking attacks. The remaining stories were later written down in manuscripts during the 11th and 12th centuries. Earlier manuscripts, written in the Irish language, date back 300 to 400 years before that.
History of the Tuatha Dé Danann
The Tuatha Dé Danann were god-like people who traveled to Ireland by ship and lived there before the native Irish. They arrived to take over the land from the Fir Bolgs, who were already living in northern Ireland. The Tuatha Dé Danann were seen as gods because of their advanced knowledge in areas like druidry, magic, prophecy, and history. Their leader was named Nuada. He led them into battle against the Fir Bolgs near the western coast of Ireland, where the Tuatha had landed by ship. Many Tuatha Dé Danann died in this war, but even more Fir Bolgs were killed, including their leader, Eochai Mac Erc.
The Tuatha Dé Danann came from another world but lived in Ireland until they were driven out by a war with a semi-demonic group called the Fomorians. The Fomorians lived on the edges of Ireland. Their king was named Balor in mythology. After the Tuatha Dé Danann lost a battle to the Milesians, they were forced to live underground in the Sidhes. The Sidhes were underground chambers beneath the surface of Ireland. Though hidden from the world, they sometimes came above ground on special days like Halloween and May Day.
In addition to individual poems, many poems are included in longer stories and writings. Some of these are found in the pseudohistorical text Lebor Gabála Érenn and works by Keating.
Examples include:
• Arsaidh sin a eóuin Accla ("Fintan and the Hawk of Aicill")
• Coire Érmai / Coire Goriath ("The Cauldron of Poesy")
The collected stories include both mythological and non-mythological content. For example, The Fitness of Names (#149–159, etc.) explains the meanings of names like Dian Cecht. Irish onomastica, such as the Dindshenchas, also include stories about gods like Boann (associated with Inber Colptha), the Dagda (associated with Fidh nGaible), and Brecan (associated with Coire Brecain). These stories often appear in detailed poems or prose. Genealogical records, the Roll of the Kings, and notes in texts like the law treatise Senchus Mor also provide information.
Examples of other texts include:
• Banshenchas ("History of Women") by Dobbs (1932)
• Cóir Anmann ("The Fitness of Names") by Stokes (1897)
• Dindsenchas ("Lore of Places")
• Sanas Cormaic ("Cormac's Glossary") by Nes[s] (Nescoit)
• Triads of Ireland: mentions of the indeoin Dagdai (the Dagda’s ox) and others
Other texts include:
• Chronicon Scotorum
• Lebor Gabála Érenn
• Glas Gaibhnenn
The following prose stories are discussed in more detail in the next section.
Survey of prose tales
The gods from the euhemerised myths arrived in five groups through migrations, as described in the Lebor Gabála Érenn (Book of Invasions). However, the detailed stories of each migration (called tochomlada in Irish) were not fully preserved. Instead, the Lebor Gabála Érenn includes brief summaries of these migration tales. Other stories, such as the tale of Tuan mac Cairill and the Fintan mac Bóchra dialogue, describe Tuan and Fintan as ancient beings from a time before the Great Flood. They were reborn as different creatures, and their stories are also mentioned in the Lebor Gabála Érenn.
The battle stories (catha in Irish), such as the First and Second Battle of Moytura (also called the Battles of Mag Tuired), are fully preserved in manuscripts from the 16th century. However, other important battle tales, like the Cath Tailten (Battle of Tailten) or Orgain Tuir Chonaind (Massacre of Conan's Tower), are not fully recorded. These stories are only briefly summarized in the Lebor Gabála Érenn.
The late story Oidheadh Chloinne Tuireann (The Fate of the Children of Tuireann) explains how Lugh punishes the sons of Tuireann for killing his father, Cian. Lugh forces them to gather magical items and weapons that will be used in the Second Battle of Mag Tuired against the Fomorians. An earlier version of this story in the Lebor Gabála Érenn includes a different list of punishments and does not mention the murder happening before the battle.
In Oidheadh Chloinne Lir (The Fate of the Children of Lir), the four children of Lir are turned into swans by their jealous stepmother. They live as swans for many years until Christian times, when they are converted, changed back into humans, and die very old.
The story Tochmarc Étaíne (The Wooing of Étaín) begins with the birth of Aengus, who is the son of the gods Dagda and Boann. Aengus wins the home of the Brú na Bóinne from Boann’s husband, Elcmar. The story then follows Étaín, who becomes the wife of Midir. After Midir’s jealous first wife, Fuamnach, turns Étaín into a fly and drives her away, Étaín becomes Aengus’s companion. Later, Fuamnach drives Étaín away again, and she is swallowed by a human woman, who later gives birth to her as a daughter. Étaín’s beauty attracts the High King, Eochaid Airem, who marries her. Eventually, Midir uses magic to win Étaín back.
The Lebor Gabála Érenn also mentions a story about Goídel Glas, the legendary ancestor of the Gaelic people and the creator of the Gaelic language. It claims that Goídel Glas was cured of a snake bite by Moses’s rod. However, some scholars, like Macalister, believe this story was made up by later writers.