In ancient writers there is no information as to the views prevalent among the Celts regarding the forms or the abodes of the spirits of the dead, beyond the statement that the Druids taught the doctrine of their re-birth. We are thus compelled to look to the evidence afforded by myth, legend, and folk-lore. These give fair indications as to the types of earlier popular belief in these matters, but it would be a mistake to assume that the ideas embodied in them had remained entirely unchanged from remote times. The mind of man at certain levels is quite capable of evolving new myths and fresh folk-lore along the lines of its own psychology and its own logic. The forms which the soul could take doubtless varied greatly in men's opinions in different districts and in different mental perspectives, but folk-lore tends to confirm the view that early man, in the Celtic world as elsewhere, tended to emphasise his conception of the subtlety and mobility of the soul as contrasted with the body. Sooner or later the primitive philosopher was bound to consider whither the soul went in dreams or in death. He may not at first have thought of any other sphere than that of his own normal life, but other questions, such as the home of the spirits of vegetation in or under the earth, would suggest, even if this thought had not occurred to him before, that the spirits of men, too, had entrance to the world below. Whether this world was further pictured in imagination depended largely on the poetic genius of any given people. The folk-lore of the Celtic races bears abundant testimony to their belief that beneath this world there was another. The 'annwfn' of the Welsh was distinctly conceived in the folk-lore embodied in mediaeval poetry as being 'is elfydd' (beneath the world). In mediaeval Welsh legend, again, this lower world is regarded as divided into kingdoms, like this world, and its kings, like Arawn and Hafgan in the Mabinogi of Pwyll, are represented as being sometimes engaged in conflict. From this lower world had come to man some of the blessings of civilisation, and among them the much prized gift of swine. The lower world could be even plundered by enterprising heroes. Marriages like that of Pwyll and Rhiannon were possible between the dwellers of the one world and the other. The other-world of the Celts does not seem, however, to have been always pictured as beneath the earth. Irish and Welsh legend combine in viewing it at times as situated on distant islands, and Welsh folk-lore contains several suggestions of another world situated beneath the waters of a lake, a river, or a sea. In one or two passages also of Welsh mediaeval poetry the shades are represented as wandering in the woods of Caledonia (Coed Celyddon). This was no doubt a traditional idea in those families that migrated to Wales in post- Roman times from Strathclyde. To those who puzzled over the fate of the