Eochaid (or Eochu) Ailtlethan ("broad blade"), son of Ailill Caisfiaclach, was, according to medieval Irish legends and historical traditions, a High King of Ireland. According to the Lebor Gabála ÃÂrenn, he took the throne after overthrowing and killing the previous incumbent, Adamair. He ruled for eleven years, until he was killed in battle by Fergus Fortamail. The Lebor Gabála ÃÂrenn synchronises his reign with that of Ptolemy V Epiphanes in Egypt (204âÂÂ181 BC). The chronology of Geoffrey Keating's Foras Feasa ar ÃÂirinn dates his reign to 285âÂÂ274 BC, that of the Annals of the Four Masters (which gives him a reign of seventeen years) to 414âÂÂ396 BC.