It is clear that there was a definite tradition assigning to Amolngaid twenty years, to Ailill Molt eleven years, and Duach twenty years; and that the chronologer, whom O’Duinn followed, did not venture to tamper with these numbers in order to account for the missing years. As for Ailill Molt, twenty years are assigned to him in the list in the _Book of Leinster_. But this may be at once rejected; for twenty years represent the duration of his reign as king of Ireland (462-482), and it is highly improbable that the throne of Connaught became vacant at the same moment as the throne of Ireland. Accepting then eleven years as the genuine tradition, he must have succeeded to Connaught _c._ 471, as he died in 482, and there is no reason to suppose that he resigned the kingship of Connaught before his death. The interval from 482 to 502 is exactly covered by the twenty years assigned to Duach Tenga Uma. If Amolngaid followed Dathi in 428 and reigned for twenty years, the end of his reign would fall _c._ 448, which would correspond to the record in the _Annals of the Four Masters_ (449). Thus we should arrive at an interval of about twenty-four years between Amolngaid’s death and Ailill Molt’s succession (448-471), which is unaccounted for. [The confusion of Ailill Molt’s regnal years in Connaught with his twenty regnal years in Ireland served to shorten this period by nine years; and in the list of the _Book of Leinster_ the residue of the chronological error is “corrected” by adding fourteen years to the reign of Amolngaid, to whom thirty-four years are assigned.] The question therefore is, who reigned in Connaught between Amolngaid and Ailill Molt? Now I think it can hardly be insignificant that in the Annals as well as in the lists Duach Tenga Uma is reduplicated. This must have had some motive, and the most probable explanation seems to be that two Duachs did reign in Connaught, and that O’Duinn is right in distinguishing Duach son of Brian from Duach son of Fergus, though he confuses the order and chronology. For it is clear that he had knowledge of Duach Galach son of Brian, whom he describes as falling in battle with the Cinel Eogain. His notice of this king is as follows (I use the text and translation furnished by Mr. E. J. Gwynn):— Duach mac Briain abus | Duach son of Brian next XX bliadan a flaithus, | was sovereign 20 years; fuair a brath, ba tennel tair, | he met his betrayal—he was a prince | in the east—in ’sa cath re ceinel Eogain. | battle with the cinel Eogain.