Rechtaid Rígderg ("red king"), son of Lugaid Laigdech, was, according to medieval Irish legend and historical tradition, a High King of Ireland. He took power after killing

Macha Mong Ruad Macha () was a sovereignty goddess of ancient Ireland associated with the province of Ulster, particularly the sites of Navan Fort (''Eamhain Mhacha'') and Armagh (''Ard Mhacha''), which are named after her.Koch, John T. ''Celtic Culture: A His ...

, daughter of his father's killer, Áed Rúad. He ruled for twenty years, until he was killed by

Úgaine Mór Úgaine Mór, son of Eochu Buadach, son of Dui Ladrach, was, according to medieval Irish legend and historical tradition, the 66th High King of Ireland. Biography He was the foster-son of Cimbáeth and Macha Mong Ruad and he took power by killing ...

, foster-son of Macha and her husband Cimbáeth. 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 ...

'' synchronises his reign to that of

Ptolemy I Soter Ptolemy I Soter (; gr, Πτολεμαῖος Σωτήρ, ''Ptolemaîos Sōtḗr'' "Ptolemy the Savior"; c. 367 BC – January 282 BC) was a Macedonian Greek general, historian and companion of Alexander the Great from the Kingdom of Macedon ...

(323–283 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 ...

's ''Foras Feasa ar Éirinn'' dates his reign to 461–441 BC, 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 In the history of Europe, the Middle Ages or mediev ...

'' to 654–634 BC.''Annals of the Four Masters'
M4546-4566
/ref> If a son of the legendary 2nd century AD Lugaid Loígde, Rechtaid Rígderg appears to have been misplaced chronologically by the later medieval synchronists.

References

Legendary High Kings of Ireland 5th-century BC rulers Usurpers 5th-century BC murdered monarchs {{Ireland-royal-stub