He was also abbot of Emly from 851 to 872, an important monastery in County Tipperary where he succeeded a previous King of Munster, Ólchobar mac Cináeda (died 851).
He was originally considered a member of the Eóganacht Airthir Cliach as a 5th generation descendant of Cormac Sriabderg, brother of Fergus Scandal mac Crimthainn (died 582), King of Munster.
[1] Recent research has shown this pedigree to be faulty and it is more likely he was of the Eóganacht Áine branch and a 6th generation descendant of Garbán mac Éndai (flourished 596), King of Munster.
The King of Munster, Máel Gualae mac Donngaile (died 859), was then captured by the Norse and stoned to death.
In 860, the men of Munster accompanied the forces of the high king in his expedition to the north against the Northern Ui Neill.