This is the Death of Eochaidh son of Mairid
From the Book of the Dun Cow
Translated by Standish O'Grady. Silva Gaedelica V.II.

A good king that ruled over Munster: Mairid son of Cairid. He had two sons: Eochaid and Ribh. Guaire’s daughter Eibhliu, from the brugh of the mac óg, ‘tis she was wife to Mairid. Upon his son, on Eochaid, she pitched her fancy (now from this Eibhliu it is that slaibh Eibhlinne or "Eibhliu’s mountain" is named). For a long time she solicited the young man, and at last pressed him hard that privily he should fly with her. Ribh told his brother that rather than disgrace himself he ought to carry off the woman, and that he would himself quit the country with him.

With Eibhliu therefore Eochaid eloped, and Ribh went with them. Ten hundred was their complement of men, and the manner of their travel was with bringing of flocks and herds. Their soothsayers told them that not in the one place it was fated for them to effect a landed settlement, and they parted accordingly at bealach dá liag or "the way of two flagstones."

Ribh went westwards to "the country of Midir’s game with the mac óg," otherwise magh finn or "the white plain." Here Midir, who previously had killed their horses, came to them leading by the halter one that bore a pack-saddle. On him they loaded all their stuff, and he conveyed it to Airbthiu’s plain: the place where loch Ree is to-day. At this point the garran lay down with them, then stood up again, and in that spot burst forth a spring which in the event overwhelmed and drowned them all: the same is lock Rí or "loch Ree."

Eochaid on the other hand went on till he reached the brugh of the mac óg. A tall man came to them and would have turned them out of the country, but they went not for him. That night the man killed all their horses. On the morrow he returned to them and said: “unless ye quit the land on which ye stand, to­night I will slay all your people.” Eochaid answered: “great mis­chief hast thou wrought us already, to have killed all our horses; without which we could not, even though we desired it, depart.” Angus [or the mac óg, for he it was] gave them a great horse, and on him they clap all their gear; he enjoined them moreover not to unload the horse [on the way], nor [at any time] to let him make a halt, lest where he stood there happened that which should be to them an occasion of their death. Upon a Sunday then in ‘mid-harvest month,’ or September, they set out and so to liathmuine or ‘grey bramble-bush’ in Ulidia, where the whole of them gather to the horse and with one motion relieve him of all their impedimenta; but never a one of them turned his head back along the way by which they were come. The animal stood with them therefore, and here too there was a spring well. Over this Eochaid had a house made, with a flap to cover the well and a woman to tend it continually; and against Muiredach son of Fiacha he in the sequel made good his claim to the half- rule of Ulidia.

But once on a time that the woman had not shut down the well, linn muine or ‘the bramble-bush water’ rose and covered liathmuine above; there Eochaid was drowned with his children, all but Liban and Conaing, and Curnan the half-wit from whom are the dál mBuain and the dál Saline; which latter indeed ever and anon had foretold to them how that the loch would overrun them, saying:--

“Come ye, come ye, grasp edged tools and hew you vessels out: with a grey flood linn muine shall whelm liathrnuine; in the broad water Aire and Conaing shall be drowned; swim east and west and up and down through every sea!

And this was true for him; for by the space of three hundred years Liban ranged the sea, with her lap-dog in form of an otter close after her whichever way she went and never parting from her at all. Herself it was that to Beoan son of Innle when he caught her in his nets told all her fortunes, on which occasion she chanted these words which follow:--

“Beneath loch nEchach I have my dwelling now: high above me is the once solid surface which troops of horses trod; under ships’ rounded hulls is my appointed place; the wave it is my roof, the shore my wall . .

This then was what most contributed to disperse the Ulidians throughout Ireland: the eruption of lock nEchach or ‘loch Neagh’ namely. After her baptism another name was conferred on Liban:
muirghein or ‘sea-birth,’ that is to say [a compound meaning] gem mara or ‘birth of the sea.’ As for one half of her ‘tis a salmon it was, the other being human; and for her it was that the sennachie sang these quatrains:--

“A sea-birth that is a birth fraught with special virtues the daughter of haughty Eochaidh is...

Liban and Airiu were Eochaidh Finn’s two daughters; Airiu wife of Curnan was drowned there, and he died of grief for her: hence carn Curndin or ‘Curnan’s cairn’ has its name, and that is ‘the invention of Curnan.’
Now for a full year Liban had been in her bower beneath the loch and her lap-dog with her there, God preserving her the while from the waters of loch Neagh, when she said one day: “O Lord, happy the one that should be in the salmon’s shape, scouring the sea and swimming even as they do!” Then she was turned into salmon’s form, and her lap-dog into an otter’s; so that whatever the course she took, and into what airt soever, - he was immediately in her wake under the waters and the seas. In which wise she continued from the time of Mairid’s son Eochaid to that of Comgall of Bennackar or ‘Bangor.’
From tigh Dabheoc the same Comgall despatched Beoan mac Innle to have speech of Gregory and to bring back canonical order and rule. As Beoan’s people therefore navigated the sea, from under the currach they heard a chant as of angels and Beoan qnestioned: “whence this song?“ “It is I that make it,” answered Liban. “Who art thou ?“ Beoan pursued. “Liban daughter of Mairid’s son Eochaid am I.” “And what causes thee to be in this fashion?" She said: “for now three hundred years I am beneath the sea; and the purpose for which I am come is to tell thee that I will go westwards to meet thee at innbher Oiorba. On this very day twelvemonth then, and for - sake of the saints of Dalaradia, be my tryst kept by you; all which tell thou to Comgall and to the other saints as well.” “That will I not unless its price be paid me,” said Beoan. - “What is the price thou askest ?“ “That I have thee buried in mine own monastery.” “Verily thou shalt have that,” she replied. Beoan subsequently returned from the eastward, and to Comgall with the rest of the clergy told all the story of the muirgheilt or mermaid.
Thus the year ran out; [at the place appointed on the coast] the nets were made ready, and she was taken in that of Fergus - from Meelick. She was brought to land, her form and her whole description being wonderful. Numbers came to view her - and she in a vessel with water round about her.
Like every one else the chief of the úi Chonaing was there, and he wore a crimson mantle. This she eyed persistently, and the warrior as it were enquired of her, saying: “if it be that thy mind is bent on the mantle it shall be thine.” “Nay,” she answered: “by no means is it to that end I observe it, but because on the day in which he was drowned it was a crimson mantle that Eochaid wore. Nevertheless,” she added, “in guerdon of this thine offer to me good luck be upon thee and on ‘the man of thy place’ [i.e. thy successor]; neither in any convention where he shall find himself be it ever needful to ask which is thy repre­sentative.”

There came up a great swart larech, uncouth of aspect, and killed her lap-dog. To him and to his ribe she bequeathed that never should they triumph over any but ignoblest foes nor, till such time as they should fast at her shrine, avail to take vengeance for ills done to them. Hereupon the óglaech made genuflexion to her.

Now arose a contest for her possession: Comgall saying that, since it was in his country she was caught, she was his; Fergus maintaining that, since it was into his net she had chanced, she must be his; while Beoan again affirmed her to be his property, - for that so she herself had promised to him. Accordingly those saints fasted all, in order that concerning this their dispute God should deliver judgment as between them.

To a certain man there an angel said: “from ‘cam Airenn’ or ‘Airiu’s cairn’ will come two stags; upon these yoke ye the chariot [in which she is], and whatever be the direction in which they carry her let them be. On the morrow the deer came as - the angel had proclaimed, and bore her away to tech Dabheoc. Then the clergy gave her her choice: whether to be baptised and then and there presently go to Heaven; or to be continued in life for the same length of time again [3oo years], and so to go to Heaven after life prolonged beyond many ages. The election she made was to depart then. Comgall baptised her, and the - name that he conferred on her was Muirghein or "sea-birth," as before; or perhaps Muirgheilt, i.e. "sea-prodigy," that is to say geilt in mhara or "the prodigy of the sea." Fuinche too was another name for her.

In that place wonders and miracles are wrought through her, and there she (after the manner of every other sainted virgin) enjoys honour and reverence even as God hath bestowed them on her in Heaven.

Finis.

SOURCE

Silva Gadelica. ed. and trans. Standish Hayes O'Grady. 1892. reprint: NY: C. Lemma Publishing Corporation, 1970.