Eochaid (or Eochu) Ailtlethan ("broad blade"), son of Ailill Caisfiaclach, was, according to medieval Irish legends and historical traditions, a

High King of Ireland High King of Ireland ( ga, Ardrí na hÉireann ) was a royal title in Gaelic Ireland held by those who had, or who are claimed to have had, lordship over all of Ireland. The title was held by historical kings and later sometimes assigned ana ...

. According to the ''

Lebor Gabála Érenn ''Lebor Gabála Érenn'' (literally "The Book of the Taking of Ireland"), known in English as ''The Book of Invasions'', is a collection of poems and prose narratives in the Irish language intended to be a history of Ireland and the Irish fro ...

'', he took the throne after overthrowing and killing the previous incumbent,

Adamair Adamair (Adammair, Adhamair, Amadir), son of Fer Corb, was, according to medieval Irish legends and historical traditions, a High King of Ireland. He came from Munster, killed the previous incumbent, Ailill Caisfhiaclach, and reigned for five ye ...

, and ruled for eleven years, until he was killed in battle by

Fergus Fortamail Fergus Fortamail ("strong, prevailing"), son of Bresal Brecc, son of Óengus Ollom, son of Ailill Bracan, son of Labraid Loingsech, was, according to medieval Irish legend and historical tradition, a High King of Ireland. He took power after killin ...

. The ''

'' synchronises his reign with that of

Ptolemy V Epiphanes egy, Iwaennetjerwymerwyitu Seteppah Userkare Sekhem-ankhamun Clayton (2006) p. 208. , predecessor = Ptolemy IV , successor = Ptolemy VI , horus = '' ḥwnw-ḫꜤj-m-nsw-ḥr-st-jt.f'Khunukhaiemnisutkhersetitef'' The youth who ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

(204–181 BC). The chronology of

Geoffrey Keating Geoffrey Keating ( ga, Seathrún Céitinn; c. 1569 – c. 1644) was a 17th-century historian. He was born in County Tipperary, Ireland, and is buried in Tubrid Graveyard in the parish of Ballylooby-Duhill. He became an Irish Catholic priest and a ...

's ''Foras Feasa ar Éirinn'' dates his reign to 285–274 BC, that of the ''

Annals of the Four Masters The ''Annals of the Kingdom of Ireland'' ( ga, Annála Ríoghachta Éireann) or the ''Annals of the Four Masters'' (''Annála na gCeithre Máistrí'') are chronicles of medieval Irish history. The entries span from the Deluge, dated as 2,24 ...

'' (which gives him a reign of seventeen years) to 414–396 BC.''

'
M4787-4804
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References

Legendary High Kings of Ireland 3rd-century BC rulers {{Celt-myth-stub