1 The son of Niall Noígiallach[of the Nine Hostages], who sometimes bears the patronymic mac Néill Noígiallaig; founder of the kingdom of Tír Eógain [Tyrone] in north-west Ulster. Together with his brother Conall Gulban and Énna (3) constituted the rapacious Three Collas, who destroyed Emain Macha. He is thought to have seized the fortress of Ailech some time in the 5th century (c.425?) and founded the line of kings there.
2 Legendary Connacht king whose name is remembered in a place-name story. After he was killed fighting invading Ulster warriors, his body was buried facing the adversaries' territory under the presumption that his spirit would continue the defence of the homeland. To negate his power, Ulstermen exhumed his body and reburied it, face down, near Loughill; cf. ModIr. Leamhchoill, ‘elm wood’.
3 Son of Ailill Aulomm, and a legendary king of Munster, to be distinguished from his grandfather, Eógan Mór, an even betterknown king of Munster. Eógan (3) gave his name to the Eóganacht dynasty of Munster despite losing the struggle for succession. His dispute with his brother Lugaid mac Con begins when the two of them hear wonderful music drifting down from a yew tree over a waterfall; both brothers want the music maker, Fer Í, the son of Eógabal, but he disappears before either can have him. Contention arises between the brothers until they meet in the Battle of Cenn Abrat. Lugaid's fool, Do Dera, believes that his master will be defeated and killed, and so takes his place on the battlefield and dies in his stead. Although Eógan knows he has not killed his brother when he sees his distinctive white legs on a fleeing warrior, he cannot prevent Lugaid's escape to Scotland. Several commentators have suggested that the legendary Battle of Cenn Abrat may be based on the historical defeat of the invading Érainn.
The brothers' fortunes are reversed when next they meet on the battlefield of Mag Mucrama (Co. Galway). Lugaid has raised a huge army, which includes Scottish allies and the blind druid Dil Maccu Crecga of Osraige[Ossory], who puts a spell on Eógan. Once Dil senses that Eógan will not survive the battle, he asks the king to lie with his daughter Moncha, so that his descendants may become kings of Munster. Nine months later Moncha gives birth to Fiachu Muillethan, the beginning of the Eóganacht dynasty. In the battle Eógan and six other sons of Ailill Aulomm fall, and Lugaid succeeds to the crown, later taking Cormac mac Airt as a foster-son. Many commentators see a parallel between Eógan's fathering of Fiachu and Art's fathering of Cormac, both with common women on the nights before they went to their deaths.