Ailill mac Echach Mugmedóin was an Irish prince, the son of the high king Eochaid Mugmedón (d.362)[1] by his wife Mongfind, sister of Crimthann mac Fidaig (d.367).
According to this saga, his half-brother the high king Niall Noigiallach (d.405) made Ailill's full brother Fiachrae his champion and levier of rents and hostages on the death of their brother Brion.
After Fiachrae's death, Ailill was captured and executed by Eochaid mac Crimthainn of Munster.
According to legend, he was buried at Heapstown Cairn, County Sligo.
[3] This biography of a member of an Irish royal house is a stub.