 He served in this capacity for over thirty years, dying in 1174.Gilla Mo Chaidbeo's death is the last to be commemorated in the "Félire húi Gormáin" or Martyrology of Gorman, which was written by his contemporary Máel Muire Ua Gormáin (Marianus Gorman) sometime in the second half of the 12th century.The preface suggests that it was written between Ruaidrí Ua Conchobair's accession to the high-kingship in 1166 and the death of Gilla meic Liac mac Diarmata (Gelasius.