Saorbhreathach is listed as Lord of Eoghanacht, one of the seats of the ancient kingdom of Eóganachta in what is now part of Republic of Ireland.
An early king and semi-mythological ancestor of the Eóganachta and Uí Fidgenti, Ailill Aulom, is then found at the fortress in the Cath Maige Mucrama cycle.
Cormac mac Cuilennáin of the Eóganachta of Cashel, King of Munster, with his "evil genius" and later successor Flaithbertach mac Inmainén by his side, raided Connaught and Leinster in retaliation and, according to some annals, defeated Flann.
The Ó Dálaigh who settled in Munster seem to have been given an alternative descent from the Eóganacht kings of Cashel, in particular from Aenghus the king of Cashel who was baptised by St. Patrick.