Dui Dallta Dedad ("foster-son of Deda mac Sin"), son of Cairpre Lusc, son of Lugaid Luaigne, was, according to medieval Irish legend and historical tradition, a High King of Ireland. He took power after killing his predecessor, and his grandfather's killer, Congal Cláiringnech, and ruled for ten years, at the end of which he was killed by Fachtna Fáthach in the battle of ÃÂrd Brestine. The Lebor Gabála ÃÂrenn synchronises his reign with that of Ptolemy XII Auletes (80âÂÂ51 BC) in Egypt and the civil war between Pompey and Caesar in Rome (49 BC). The chronology of Geoffrey Keating's Foras Feasa ar ÃÂirinn dates his reign to 120âÂÂ110 BC, that of the Annals of the Four Masters to 169âÂÂ159 BC.