Of uncertain origins, Dáire Cerbba is named in many early and late sources as the grandfather of the semi-mythological Mongfind and Crimthann mac Fidaig, and the most frequently named early ancestor of the historical Uí Liatháin and Uí Fidgenti. All of these are historically associated with the province of Munster, but according to the early manuscript Rawlinson B 502, Dáire Cerbba was born in Brega, County Meath, and got his epithet from a location there. This is otherwise unexplained. He may or may not have been a relative of Conall Corc, the founder of the Eóganachta dynasty. He is often confused or paired with Maine Munchaín, who may be his father or twin brother, depending on the source, or this is an alias and the two people are the same. Both are listed in the surviving genealogies as sons of Ailill Flann Bec, grandfather of Conall Corc, but the arrangement changes from source to source. O'Keefe's translation of the Book of Munster set forth the relationship of the several generations of this group as follows: Fiachu Muillethan had three sons: Oilill Flann Mor, Oilill Flann Beag and Deachluath. The latter, Deachluath, is ancestor of the tribe called Uí Fiachach Eile and Oilill Flann Mor left no issue. Oilill Flann Beag had four sons:
Fiodach, to him was son Criomthann Mor mac Fiodhaig and who took the fortress of Doire Da Broc from his nephews, the sons of Eochaid Mugmeadhon i.e., from Brian, Fiachra, Oilill and Feargus. Crimthann's sister Mongfind was mother of those four sons. So that her son, Brian, would get the kingship of Ireland, she plotted to poison her brother, Criomthann; the latter died of that poisonous drink; Mungfionn herself died as well at Inish Donglais on the Moy - as she tasted the drink in order to induce her brother to drink from it. Crimthann, having drunk it, came to Sliabh Uidhe on Riogh "The Mountain of the King's Death" and there died. Mongfind is simply called the daughter of Daire, not of Fidach, in the Book of Lismore, and there Daire's father is called Findchad, while Crimthand Mór is not mentioned at all. Thus the alternative exists that they were not originally brother and sister. Maine Munchaoin and Daire Cearba were noted as twins, and some manuscripts attribute Maine's offspring as being fathered by Daire due to Maine's inability; as a result, Maine tends to be overlooked as an ancestor, and the Ui Fidgheinte typically list Daire as their progenitor. Rawlinson B502, the primary source manuscript, also sets forth the Ui Fidgheinte as being descended from Daire Cearba. Daire Cerbba is credited as the ancestor of the Ui Fidgheinte and thus the O'Donovan family, and was referred to in a poem addressed to Donal II O'Donovan, chief of Clan Cathail, in as late as the early 17th century, by the bardic poet Tadhg Olltach Ó an Cháinte. Modern descendants of Daire Cerbba include the O'Connells of Derrynane, Daniel Charles, Count O'Connell having explicitly declared this to the heralds of Louis XVI of France. Also was Michael Collins, descending from the Ó Coileáin of Uí Chonaill Gabra, once the most powerful sept of the Uí Fidgenti.
In a strange passage in the notably peculiar Munster epic Forbhais Droma Dámhgháire, Daire Cerbba is said to have been king of Medón Mairtine, known to historians as the ancient capital of the Mairtine, a once prominent Érainn people. In fact the passage gives it the alternative names of "... Ardchluain na Féne and Mucfhalach Mac Daire Ceirbe. This Ceirbe was king of Meáin Mairtine. This area is called Emly today..." However it does not specifically state that Dáire belonged to the Mairtine themselves, and perhaps of importance is the fact that this site was historically occupied by the Eóganachta, for whom it was their chief church, namely Emly, which the author of FDD obviously recognizes. The Mairtine themselves belong only to prehistory and legend, but may be in part ancestral to the later Déisi Tuisceart and famous Dál gCais.
