Flathróe mac Fiachrach

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Flathróe mac Fiachrach (died 774) was a Dál nAraidi king of the Cruthin in Ulaid, a medieval over-kingdom in Ireland. He was the son of Fiachra Cossalach (died 710), a previous king.Mac Niocaill, pg.138 He may have belonged to the Eilne branch of the family. He ruled from 749-774.

Nothing is recorded of his reign in the annals but his death notice is significant in that it was the last time the title king of the Cruthin was used for the kings of Dál nAraidi.Annals of Ulster, AU 774.6

Flathróe mac Fiachrach's genealogy is recorded in Leabhar na nGenealach as; "Oilill s. Cumascach s. Flannagán s. Eochaid s. Breasal s. Flaithrí s. Fiachra Cos-salach s. Dúnghalach s. Scannal s. Béice s. Fiachra Crach, who is Teallán s. Baodán s. Eochaidh.".Dubhaltach Mac Fhirbhisigh; Nollaig Ó Muraíle, editor (2004). Leabhar na nGenealach: The Great Book of Irish Genealogies. DeBurca Books, Dublin. Volume 2, page 403. It says, quote; "Oilill s. Cumascach s. Flannagán s. Eochaid s. Breasal s. Flaithrí s. Fiachra Cos-salach s. Dúnghalach s. Scannal s. Béice s. Fiachra Crach, who is Teallán s. Baodán s. Eochaidh."