Cairbre Nia Fer
The earliest reference to Cairbre is in Tírechán's Memoir of St. Patrick, a 7th-century Latin text found in the Book of Armagh. Patrick finds an enormous grave and raises its giant occupant from the dead. The giant says he was killed by the sons of Mac Con during the reign of Cairbre Nia Fer, a hundred years previously – i.e. in the 4th century.
The 11th century Lebor Gabála Érenn places him during the reign of the High King Eterscél, which it synchronises his reign with that of the Roman emperor Augustus (27 BC - AD 14) and the birth of Christ, and makes him a contemporary of the provincial kings Conchobar mac Nessa of the Ulaid, Cú Roí of Munster and Ailill mac Máta of Connacht. Mac Con of the Dáirine, placed a generation before Cairbre by Tírechán, is dated many generations after him, to the late 2nd century, in the Lebor Gabála.
Alongside Conchobar, Cú Roí and Ailill, Cairbre appears as king of Tara in stories of the Ulster Cycle, where he is the brother of Ailill mac Máta, husband of Medb of Connacht. His wife is Fedelm Noíchrothach, daughter of Conchobar, and they have a son, Erc, and a daughter, Achall. In Cath Ruis na Ríg ("The Battle of Rosnaree"), he and his brother Find mac Rossa, king of the Gailióin of Leinster, fight a battle against Conchobar and the Ulaid. The Ulaid hero Cúchulainn kills him with a spear from distance, then decapitates him before his body hits the ground. After the Ulaid win the battle, Cairbre's son Erc swears allegiance to Conchobar, marries Cúchulainn's daughter Finnscoth, and becomes king of Tara in his father's place.
- T. F. O'Rahilly, Early Irish History and Mythology. Dublin Institute for Advanced Studies. 1946. pp. 11, 138 ff., 143 ff., 168, 177-9, 201, 285
- Ludwig Bieler (ed. & trans.), The Patrician Texts in the Book of Armagh, Tírechán 40
- R. A. Stewart Macalister (ed. & trans.), Lebor Gabála Érenn: The Book of the Taking of Ireland Part V, Irish Texts Society, 1956, p. 299-301
- R. A. Stewart Macalister (ed. & trans.), Lebor Gabála Érenn: The Book of the Taking of Ireland Part V, Irish Texts Society, 1956, p. 337
- Edmund Hogan (ed. & trans), Cath Ruis na Ríg for Bóinn, Todd Lecture Series, 1892
- Whitley Stokes (ed. trans.), "Cuchulainn's death, abridged from the Book of Leinster", Revue Celtique 3, 1877, pp. 175-185
- Edward Gwynn (ed. & trans.), The Metrical Dindshenchas Vol 1: "Achall", Dublin Institute for Advanced Studies, 1902