Cathal mac Donnubáin

Cathal mac Donnubáin is the second known son of Donnubán mac Cathail, king of Uí Fidgenti and an ancestor of the medieval and modern O'Donovan family. He may have succeeded his brother Uainide mac Donnubáin as King of Uí Chairpre Áebda (Cairbre Eva) at his death in 982, no ruler(s) being known after that until 1014. However, this is confused by two notices of the death of Cairpre mac Cléirchín in 1013 or 1014, where in one he is styled king of Uí Chairpre and in the other of Uí Fidgenti, leaving it uncertain which Cathal might actually have been if either. Rivalry between the two families is unknown but cannot be ruled out.

Cathal led the forces and is styled king of the Uí Chairpre in the Battle of Clontarf in 1014, in the account of the Leabhar Oiris, which is believed to be based at least in part on contemporary documents. There it is said he fought on the side of Brian Bóruma, High King of Ireland in the great central division commanded by Cian mac Máelmuaid, standing against the forces of Leinster commanded by Máel Mórda mac Murchada, King of Leinster. He is not listed among the slain there. That he participated in the battle is also an O'Donovan tradition. Cathal's mention in the Leabhar Oiris is the only one found anywhere outside of an O'Donovan pedigree in all surviving sources. Not anywhere in the annals is he mentioned.

What is unknown is how early Cathal was listed in or before the Leabhar Oiris, because what has survived is a later compilation of earlier sources where the spelling has been changed to Early Modern Irish. He is listed as Cathal mac Donnabháin rí Ó g-Cairbre, whereas Cathal mac Donnubáin, rí h-Ua Cairpre would be contemporary.

It is possible that Cathal was as much as three quarters Norse in ancestry. His maternal grandfather was probably Ivar of Limerick, the last Norse king of Limerick and an ally of his father. Donnubán himself has also been argued to have had a Norse mother, a daughter of one Amlaíb, rí Gall Muman or Olaf, king of the Norse of Munster, possibly referring to Amlaíb Cenncairech. It was also assumed by John O'Donovan that Cathal married a Norse woman himself, because his only known issue is Amlaíb ua Donnubáin. A now lost source of uncertain date makes the entirely plausible claim that his son fought at Clontarf under Cian, although this is possibly a mistake for Cathal himself, or both may have.

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