I consider it next to impossible for any Gaelic pedigree to have been materially tampered with from the introduction of the art of writing, because tribal jealousies alone would have prevented it, and because each stem of the four races was connected at some point with every other stem, the whole clan system being inextricably intertwined, and it was necessary for all the various tribal genealogies to agree, in order that each branch, sub-branch, and family might fit, each in its own place. I have little doubt that the genealogy of O'Neill, for instance, which traces him back to the father of Niall of the Nine Hostages who came to the throne in 356 is substantially correct. Niall, it must be remembered, was father of Laoghaire [Leary], who was king when St. Patrick arrived, by which time, if not before, the art of writing was known in Ireland. _À fortiori_, then, we may trust the pedigrees of the O'Donnells and the rest who join that stem a little later on. If this be acknowledged we may make a cautious step or two backwards. No one, so far as I know, has much hesitation in acknowledging the historic character of that King Laoghaire whom St. Patrick confronted, nor of his father Niall of the Nine Hostages. But if we go so far, it wants very little to bring us in among the Fenians themselves, and the scenes connected with them and with Conn of the Hundred Battles; for Niall's great-grandfather was that Fiachaidh who was slain by the Three Collas--those who burnt Emania and destroyed the Red Branch--and his father is Cairbré of the Liffey, who overthrew the Fenians, and his father again is the great Cormac son of Art, son of Conn of the Hundred Battles who divided the kingdom with Owen Mór. But it is from the three grandsons of this Owen Mór the Eberians come, and from their half-brother come the Ithians, so that up to this point I think Irish genealogies may be in the main accepted. Even the O'Kavanaghs and their other correlations, who do not join the stem of Eremon till between 500 or 600 years before Christ, yet pass through Enna Cennsalach, king of Leinster, a perfectly historical character mentioned several times in the Book of Armagh,[13] who slew the father of Niall of the Nine Hostages; and I believe that, however we may account for the strange fact that these septs join the Eremonian stem so many hundreds of years before the O'Neills and the others, that up to this point their genealogy too may be trusted.