Ailill mac Echach Mugmedóin was an Irish prince, the son of the high king

Eochaid Mugmedón Eochaid Mugmedón () was a semi-legendary Irish king. According to medieval Irish legend and historical tradition, Eochaid was a High King of Ireland, best known as the father of Niall of the Nine Hostages and ancestor of the Uí Néill and Co ...

(d.362) by his wife

Mongfind Mongfind (or Mongfhionn in modern Irish)—meaning "fair hair" or "white hair"—is a figure from Irish legend. She is said to have been the wife, of apparent Munster origins, of the legendary High King Eochaid Mugmedón and mother of his eldest ...

, sister of

Crimthann mac Fidaig Crimthann Mór, son of Fidach , also written Crimthand Mór, was a semi-mythological king of Munster and High King of Ireland of the 4th century. He gained territory in Britain and Gaul, but died poisoned by his sister Mongfind. It is possible t ...

(d.367). He was ancestor of the Uí nAilello dynasty of

Connacht Connacht ( ; ga, Connachta or ), is one of the provinces of Ireland, in the west of Ireland. Until the ninth century it consisted of several independent major Gaelic kingdoms (Uí Fiachrach, Uí Briúin, Uí Maine, Conmhaícne, and Delbhn ...

. He lived in the late 4th century. "The Violent Death of Crimthann mac Fidaig and of the Three Sons of Eochaid Muigmedón" gives the story of the sons of Eochaid Mugmedón. According to this saga, his half-brother the high king

Niall Noigiallach Niall ''Noígíallach'' (; Old Irish "having nine hostages"), or Niall of the Nine Hostages, was a legendary, semi-historical Irish king who was the ancestor of the Uí Néill dynasties that dominated Ireland from the 6th to the 10th centuries. ...

(d.405) made Ailill's full brother

Fiachrae Fiachrae was an Irish prince, the son of the high king Eochaid Mugmedón (d.362) by his wife Mongfind, sister of Crimthann mac Fidaig (d.367).Francis J.Byrne, ''Irish Kings and High-Kings'', Table 1 He was ancestor of the Uí Fiachrach dynasties o ...

his champion and levier of rents and hostages on the death of their brother Brion. Ailill accompanied Fiachrae on a successful raid into Munster but Fiachrae was mortally wounded. After Fiachrae's death, Ailill was captured and executed by Eochaid mac Crimthainn of Munster. According to legend, he was buried at

Heapstown Cairn Heapstown Cairn is a cairn and National Monument located in County Sligo, Ireland. Location Heapstown Cairn is located on a low hill immediately west of the River Uinshin and north of Lough Arrow, northwest of Ballindoon Friary. History H ...

, County Sligo.

Notes

References

* Francis J.Byrne, ''Irish Kings and High-Kings'' * ''The Chronology of the Irish Annals'', Daniel P. McCarthy
Dan Wiley's site on the Cycles of the Kings
5th-century deaths People from County Roscommon People from County Sligo 5th-century Irish people Year of birth unknown {{Ireland-royal-stub