Circumstantial evidence can be adduced to prove that the most important portions both of Gaelic and British early literature can be safely relegated to a period of several centuries prior to their now-existing record. Our earliest version of the episode of the _Táin Bó Chuailgné_, which is the nucleus and centre of the ancient Gaelic heroic cycle of which Cuchulainn, _fortissimus heros Scotorum_, is the principal figure, is found in the twelfth-century Book of the Dun Cow. But legend tells us that at the beginning of the seventh century the Saga had not only been composed, but had actually become so obsolete as to have been forgotten by the bards. Their leader, one Senchan Torpeist, a historical character, and chief bard of Ireland at that time, obtained permission from the Saints to call Fergus, Cuchulainn’s contemporary, and a chief actor in the “Raid”, from the dead, and received from the resurrected hero a true and full version. This tradition, dealing with a real personage, surely shows that the story of the _Táin_ was known before the time of Senchan, and probably preserves the fact, either that his version of Cuchulainn’s famous deeds became the accepted one, or that he was the first to reduce it to writing. An equally suggestive consideration approximately fixes for us the earliest redaction of the Welsh mythological prose tales called the “Mabinogion”, or, more correctly speaking, the “Four Branches of the Mabinogi”.[6] In none of these is there the slightest mention, or apparently the least knowledge, of Arthur, around whom and whose supposed contemporaries centres the mass of British legend as it was transmitted by the Welsh to the Normans. These mysterious mythological records must in all probability, therefore, antedate the Arthurian cycle of myth, which was already being put into form in the sixth century. On the other hand, the characters of the “Four Branches” are mentioned without comment—as though they were personages with whom no one could fail to be familiar—in the supposed sixth-century poems contained in those “Four Ancient Books of Wales” in which are found the first meagre references to the British hero. Such considerations as these throw back, with reasonable certainty, the existence of the Irish and Welsh poems and prose tales, in something like their present shape, to a period antedating the seventh century.