Home celtic An Explanation Of The Celtic Cycles (Irish Mythology)

An Explanation Of The Celtic Cycles (Irish Mythology)

About Celtic Myths

In Irish myths, the fictional history of Ireland can be divided into three periods. The Mythological Cycle or the Book of Invasions, comprised of successive settlements of early Celtic people on Ireland, particularly the Tuatha Dé Danann and the Milesians.

The other two cycles were supposed to be set at a later time. The Ulaid Cycle deal with the reigns of Conchobor of Ulaid and Medb of Connacht, particularly the warriors of the Red Branch and its greatest hero, Cú Chulainn. The Fenian Cycle (or the Ossianic Cycle), supposed to have set in a more peaceful time of the reign of Cormac the Airt, particularly the warriors of Fianna and its greatest hero, Finn Mac Cumhaill.

Some scholars say that there was a fourth cycle, called Cycle of Kings (or Book of Kings). This was supposed to be the history of early reign of the Milesian kings.

The earlier Irish did not divided their myths and literature into cycles. These cycles were intrepretations and usages of modern scholars. The uses of cycles in Irish literature were just a convenient mean of dividing into periods for the Irish myths. All the romances and sagas of the three (or four) cycles were added into each of main manuscript, without any logical orders.

The main sources for the Irish cycles can be found in three books: the Book of the Dun Cow (1100), the Book of Leinster (1160), and the Yellow Book of Lecan (14th century). They contained a collection of Irish sagas. All three books contained the Táin Bó Cuailnge (Cattle Raid of Cooley), the largest tale in Irish myths. The “Colloquy of the Ancients” (Agallamh na Seanórach), that contained some of the stories of Finn and the Fianna, was written in 1200, but preserved in the Book of the Dean of Lismore by Sir James MacGregor, from the 16th century.

There was later Ossianic ballads containing more stories of Finn, both in Ireland and Scotland. Michael O’Clery wrote his own version of the Book of Invasions (1631). James Macpherson (18th century) was said to have discovered and translated the poem written by the bard-hero Oisin. It was however proven that it was an invention of Macpherson.


In Welsh myths, the most important collection of works was from the Mabinogion. The Mabinogion was a collection of eleven tales (twelve if you include the tale of Taliesin), including some from the Arthurian legend. These stories, like those of the Irish sagas, were based on older oral traditions (except the three Welsh romances).

The first four tales, known as the “Four Branches of Mabinogi”, was also sometimes known as the “Cycle of Peredur”, though the hero Peredur only has minor role in all four tales.



Note that the first three button below, contained a number of tales found in the Irish myths and literature. While a button on the Mabinogion contained a collection of tales found in Welsh myths. The new page, called “The Fabulous Voyages”, contained adventures of famous travellers found in the Irish and Welsh (including Arthurian) literature.

Please take the time in reading the notes in this page.


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The collection of Welsh stories can be found in the translation of the Mabinogion.

Also, some of tales of King Arthur and his knights, actually come from Welsh sources, particularly the “Culhwch and Olwen” and the “Dream of Rhonabwy”. However the three Welsh romances in the Mabinogion were greatly influences by Chretien de Troyes, who wrote his Arthurian romances.

Speaking of King Arthur, since I was going to do a section on the Arthurian legend, I’ve decided to leave out most stories associated with Arthur in the Celtic myths (eg. three Welsh romances).