Énna Derg
Énna Derg, son of Dui Finn, was, according to medieval Irish legend and historical tradition, a High King of Ireland, who took power after killing his predecessor, and his father's killer, Muiredach Bolgrach. He was called derg, red, because he had a red face. It is said that coins were first used in Ireland during his reign. He ruled for twelve years, before dying of plague in Sliab Mis, surrounded by a large number of his troops. He was succeeded by his son Lugaid Íardonn. The Lebor Gabála Érenn synchronises his reign with that of Artaxerxes I of Persia (465–424 BC). The chronology of Geoffrey Keating's Foras Feasa ar Éirinn dates his reign to 670–658 BC, that of the Annals of the Four Masters to 893–881 BC.

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Legendary High Kings of Ireland