The late and grotesque story of the Gilla Decair may be mentioned next: he was one of the Fomorach, and had a wonderful kind of horse on whose back most of Finn’s chief warriors were induced to mount. Then the Gilla Decair and his horse hurried towards Corkaguiny, in Kerry, and took to the sea, for he and his horse travelled equally well on sea and land. Thus Finn’s men, unable to dismount, were carried prisoners to an island not named, on which Dermot in quest of them afterwards landed, and from which, after great perils, he made his way to Tír fo Thuinn, ‘Terra sub Unda,’ and brought his friends back to Erin[27]. Now the number of Finn’s men taken away by force by the Gilla Decair was fifteen, fourteen on the back of his horse and one clutching to the animal’s tail, and the Welsh Triads, i. 93 = ii. 11, seem to re-echo some similar story, but they give the number of persons not as fifteen but just one half, and describe the horse as Du (y) Moroeđ, ‘the Black of (the) Seas,’ steed of Elidyr Mwynfawr, that carried seven human beings and a half from Pen Ỻech Elidyr in the North to Pen Ỻech Elidyr in Môn, ‘Anglesey.’ It is explained that Du carried seven on his back, and that one who swam with his hands on that horse’s crupper was reckoned the half man in this case. Du Moroeđ is in the story of Kulhwch and Olwen called Du March Moro, ‘Black the Steed of Moro,’ the horse ridden in the hunt of Twrch Trwyth by Gwyn ab Nuđ, king of the other world; and he appears as a knight with his name unmistakably rendered into Brun de Morois in the romance of Durmart le Galois, who carries away Arthur’s queen on his horse to his castle in Morois[28]. Lastly, here also might be mentioned the incident in the story of Peredur or Perceval, which relates how to that knight, when he was in the middle of a forest much distressed for the want of a horse, a lady brought a fine steed as black as a blackberry. He mounted and he found his beast marvellously swift, but on his making straight for a vast river the knight made the sign of the cross, whereupon he was left on the ground, and his horse plunged into the water, which his touch seemed to set ablaze. The horse is interpreted to have been the devil[29], and this is a fair specimen of the way in which Celtic paganism is treated by the Grail writers when they feel in the humour to assume an edifying attitude.
If one is right in setting Môn, ‘Anglesey,’ over against the anonymous isle to which the Gilla Decair hurries Finn’s men away, Anglesey would have to be treated as having once been considered one of the Islands of the Dead and the home of Other-world inhabitants. We have a trace of this in a couplet in a poem by the medieval poet, Dafyđ ab Gwilym, who makes Blodeuweđ the Owl give a bit of her history as follows:—
Merch i arglwyd, ail Meirchion,
Wyf i, myn Dewi! o Fon[30].
Daughter to a lord, son of Meirchion,
Am I, by St. David! from Mona.
This, it will be seen, connects March ab Meirchion, as it were ‘Steed son of Steeding,’ with the Isle of Anglesey. Add to this that the Irish for Anglesey or Mona was Móin Conaing, ‘Conaing’s Swamp,’ so called apparently after Conaing associated with Morc, a name which is practically March in Welsh. Both were leaders of the Fomori in Irish tales: see my Arthurian Legend, p. 356.
On the great place given to islands in Celtic legend and myth it is needless here to expatiate: witness Brittia, to which Procopius describes the souls of the departed being shipped from the shores of the Continent, the Isle of Avallon in the Romances, that of Gwales in the Mabinogion, Ynys Enỻi or Bardsey, in which Merlin and his retinue enter the Glass House[31], and the island of which we read in the pages of Plutarch, that it contains Cronus held in the bonds of perennial sleep[32].
Let us return to the more anthropomorphic figure of the afanc, and take as his more favoured representative the virile personage described emerging from the Fan Fach Lake to give his sanction to the marriage of his daughter with the Myđfai shepherd. It is probable that a divinity of the same order belonged to every other lake of any considerable dimensions in the country. But it will be remembered that in the case of the story of Ỻyn Du’r Arđu two parents appeared with the lake maiden—her father and her mother—and we may suppose that they were divinities of the water-world. The same thing also may be inferred from the late Triad, iii. 13, which speaks of the bursting of the lake of Ỻïon, causing all the lands to be inundated so that all the human race was drowned except Dwyfan and Dwyfach, who escaped in a mastless ship: it was from them that the island of Prydain was repeopled. A similar Triad, iii. 97, but evidently of a different origin, has already been mentioned as speaking of the Ship of Nefyđ Naf Neifion, that carried in it a male and female of every kind when the lake of Ỻïon burst. This later Triad evidently supplies what had been forgotten in the previous one, namely, a pair of each kind of animal life, and not of mankind alone. But from the names Dwyfan and Dwyfach I infer that the writer of Triad iii. 13 has developed his universal deluge on the basis of the scriptural account of it, for those names belonged in all probability to wells and rivers: in other terms, they were the names of water divinities. At any rate there seems to be some evidence that two springs, whose waters flow into Bala Lake, were at one time called Dwyfan and Dwyfach, these names being borne both by the springs themselves and the rivers flowing from them. The Dwyfan and the Dwyfach were regarded as uniting in the lake, while the water on its issuing from the lake is called Dyfrdwy. Now Dyfrdwy stands for an older Dyfr-dwyf, which in Old Welsh was Dubr duiu, ‘the water of the divinity.’ One of the names of that divinity was Donwy, standing for an early form Danuvios or Danuvia, according as it was masculine or feminine. In either case it was practically the same name as that of the Danube or Danuvios, derived from a word which is represented in Irish by the adjective dána, ‘audax, fortis, intrepidus.’ The Dee has in Welsh poetry still another name, Aerfen, which seems to mean a martial goddess or the spirit of the battlefield, which is corroborated and explained by Giraldus[33], who represents the river as the accredited arbiter of the fortunes of the wars in its country between the Welsh and the English. The name Dyfrdonwy occurs in a poem by Ỻywarch Brydyđ y Moch, a poet who flourished towards the end of the twelfth century, as follows[34]:—
Nid kywiw[35] a ỻwfyr dwfyr dyfyrdonwy