M. d'Arbois de Jubainville expresses himself in like terms. "We have no reason," he writes, "to doubt of the reality of the principal _rôle_ in this [cycle of Cuchulain];"[3] and of the story of the Boru tribute which was imposed on Leinster about a century later; he writes, "Le récit a pour base des faits réels, quoique certains détails aient été créés par l'imagination;" and again, "Irish epic story, barbarous though it is, is, like Irish law, a monument of a civilisation far superior to that of the most ancient Germans; if the Roman idea of the state was wanting to that civilisation, and, if that defect in it was a radical flaw, still there is an intellectual culture to be found there, far more developed than amongst the primitive Germans.'"[4]
"Ireland, in fact," writes M. Darmesteter in his "English Studies," well summing up the legitimate conclusions from the works of the great Celtic scholars, "has the peculiar privilege of a history continuous from the earliest centuries of our era until the present day. She has preserved in the infinite wealth of her literature a complete and faithful picture of the ancient civilisation of the Celts. Irish literature is therefore the key which opens the Celtic world."
But the Celtic world means a large portion of Europe, and the key to unlock the door of its past history is in the Irish manuscripts of saga and poem. Without them the student would have to view the past history of Europe through the distorting glasses of the Greeks and Romans, to whom all outer nations were barbarians, into whose social life they had no motive for inquiring. He would have no other means of estimating what were the feelings, modes of life, manners, and habits, of those great races who possessed so large a part of the ancient world, Gaul, Belgium, North Italy, parts of Germany, Spain, Switzerland, and the British Isles; who burned Rome, plundered Greece, and colonised Asia Minor. But in the Irish romances and historical sagas, he sees come to light another standard by which to measure. Through this early Irish peep-hole he gets a clear look at the life and manners of the race in one of its strongholds, from which he may conjecture and even assume a good deal with regard to the others.