Cycles of the Kings

The Cycles of the Kings, also known as the Kings' Cycles or the Historical Cycle are a body of Old and Middle Irish literature. They contain stories of the legendary kings of Ireland, for example Cormac mac Airt, Niall of the Nine Hostages, Éogan Mór, Conall Corc, Guaire Aidne mac Colmáin, Diarmait mac Cerbaill, Lugaid mac Con, Conn of the Hundred Battles, Lóegaire mac Néill, Crimthann mac Fidaig, and Brian Bóruma.
It was part of the duty of the medieval Irish bards, or court poets, to record the history of the family and the genealogy of the king they served. This they did in poems that blended the mythological and the historical to a greater or lesser degree. The resulting stories form what has come to be known as the Historical Cycle, or more correctly Cycles, as there are a number of independent groupings.
The kings that are included range from the almost entirely mythological Labraid Loingsech, who allegedly became High King of Ireland around 431 BC, to the entirely historical Brian Boru. However, the greatest glory of the Historical Cycle is the "Buile Shuibhne" ("The Frenzy of Sweeney"), a 12th-century tale told in verse and prose.
Suibhne, king of Dál nAraidi, was cursed by St Ronan and became a kind of half man, half bird, condemned to live out his life in the woods, fleeing from his human companions. The story has captured the imaginations of contemporary Irish poets and has been translated by Trevor Joyce and Seamus Heaney.
External links.
Dan M. Wiley's "The Cycles of the Kings Web Project" https://web.archive.org/web/20081227214217/http://www.hastings.edu/academic/english/Kings/Home.html