Airgetmar, son of
Sirlám, was, according to medieval Irish legend and historical tradition, a
High King of Ireland. The
Lebor Gabála Érenn says that, during the reign of
Ailill Finn, he killed
Fíachu Tolgrach in battle, but was forced into exile overseas by Ailill's son
Eochu, Lugaid son of
Eochu Fíadmuine, and the men of
Munster. He returned to Ireland after seven years, and, with the help of
Dui Ladrach, killed Ailill. Eochu became king, but Airgetmar and Dui soon killed him as well, and Airgetmar took power.