From A Compendium of Irish Biography, 1878
Olioll Olum, King of Munster, who died in 234, is said to have been progenitor of most of the great families of the south of Ireland. He married Sabia, daughter of Con of the Hundred Battles, ruler of the north of Ireland. He willed that after his death the sovereignty of Munster should vest alternately in the descendants of his son Eoghan Mor (the Eugenians, or Eoganachts, occupying the southern part of Munster), and those of his son Cormac Cas (the Dalcassians, occupying the northern part of the same province).
263. O'Briens, Historical Memoir of the: John O'Donoghue. Dublin, 1860.