He was the foster-son of Cimbáeth and Macha Mong Ruad and he took power by killing his predecessor (and his foster-mother's killer) Rechtaid Rígderg. The Lebor Gabála Érenn says that, as well as Ireland, he ruled "Alba to the Sea of Wight" – i.e. the whole of the island of Britain – and that "some say" he ruled all of Europe.
He married Cessair Chrothach, daughter of the king of the Gauls, who bore him twenty-two sons and three daughters. He is said to have divided Ireland into twenty-five shares, one for each of his children. For example, his son Lóegaire Lorc ruled Life and Cobthach Cóel Breg ruled Bregia. His daughter Muirisc ruled Mag Muirisce, from which Murrisk is said to have taken its name. This partitioning of the island stood for three hundred years, until the establishment of the provinces under Eochu Feidlech.
The reign of Úgaine Mór was thirty or forty years, until he was killed by his brother Bodbchad. According to the Lebor Gabála, he was succeeded directly by his son Lóegaire Lorc, although the Annals of the Four Masters and Geoffrey Keating's Foras Feasa ar Éirinn say Bodbchad was king for a day and a half until Lóegaire killed him. Cobthach Cóel Breg succeeded his brother Loegaire.
The Lebor Gabála synchronises Úgaine Mór's reign to that of Ptolemy II Philadelphus (281–246 BCE). Roderick O’Flaherty in Ogygia (1685) has his reign begin "the year in which Alexander conquered Darius" and last thirty years (331-301 BCE). The chronology of Keating's Foras Feasa ar Éirinn dates his reign to 441–411 BCE and the Annals of the Four Masters to 634–594 BCE.
- Lóegaire Lorc, High King of Ireland
- Cobthach Cóel Breg, High King of Ireland
- Muirisc, Princess of Ireland
- Lathar, Princess of Ireland
- "Ugaine More/Hugonius, 66th King of Ireland" at Genealogy.com
- R. A. Stewart Macalister (ed. & trans.), Lebor Gabála Érenn: The Book of the Taking of Ireland Part V, Irish Texts Society, 1956, p. 267-275.
- Anne Chambers, Ireland's Pirate Queen: The True Story of Grace O'Malley, New York: MJF Books, 2003, p. 16.
- Annals of the Four Masters M4566-4606
- Geoffrey Keating, Foras Feasa ar Éirinn 1.28-1.29
- Roderick O’Flaherty, Ogygia, or, a Chronological Account of Irish Events, Part III (1685) as translated by James Hely in his Volume II, Paris: 1793, p. 400.
|High King of Ireland
LGE 3rd century BC
FFE 441–411 BC
AFM 634–594 BC
| Succeeded by|