Byzantines, Romans, Kelts, Germans, and Sclavs form the five civilising peoples of mediaeval Europe. Three of them inhabited, and still inhabit, the actual body of the Continent, whereas the Byzantines were driven into the extreme southeast, and the Kelts into the extreme north-west, even farther than suited their capacities and pursuits, owing to the continued onward march of the others. It was also unfortunate for the Kelts that they were, so to say, a distinctly unhistorical and unsettled people; that they had no history of any importance; did not keep any record even of such events as occurred around them; and that other communities, distinct from themselves as regards place and speech, took but little notice of them. Hence, of the earlier history of the mediaeval Kelts, and especially of their chief branch, the Irish, we know practically nothing; and this although there is yet extant concerning them a literature which compares favourably in extent with that of any other early people. Imagination and the works of scholars, especially after the tenth century, supplied that which was painfully wanting in actuality.