By the banks of the River Boyne, where rises the great Fairy Mound now called Newgrange, there stood long ago the shining Palace of a prince of the People of Dana, named Angus. Of him it is that the lines are written—

"By the dark rolling waters of the Boyne
Where Angus Óg magnificently dwells."

When the Milesian race invaded Ireland, and after long fighting subdued the Danaans in spite of all their enchantments and all their valour, the Danaans wrought for themselves certain charms by which they and all their possessions became invisible to mortals, and thus they continued to lead their old joyous life in the holy places of the land, and their palaces and dancing-places and folk-motes seem to the human eye to be merely a green mound or rath, or a lonely hillside, or a ruined shrine with nettles and foxgloves growing up among its broken masonry.

Now, after Angus and his folk had thus retreated behind the veil of invisibility, it happened that the steward of his palace had a daughter born to him whose name was Ethne. On the same day Fand, the wife of Mananan the Sea God, bore him a daughter, and since Angus was a friend of Mananan and much beloved by him, the child of the Sea God was sent to Brugh na Boyna, the noble dwelling-place of Angus, to be fostered and brought up, as the custom was. And Ethne became the handmaid of the young princess of the sea.

In time Ethne grew into a fair and stately maiden Now in the Brugh of Angus there were two magical treasures, namely, an ale-vat which could never be emptied, and two swine whereof one was ever roasted and ready to be eaten while the other lived, and thus they were, day and day about. There was therefore always a store of food of faery, charged with magical spells, by eating of which one could never grow old or die. It came to be noticed that after Ethne had grown up she never ate or drank of the fairy food, or of any other, yet she continued to seem healthy and well-nourished. This was reported to Angus, and by him to Mananan, and Mananan by his wisdom discovered the cause of it. One of the lords of the Danaans, happening to be on a visit with Angus, was rendered distraught by the maiden's beauty, and one day he laid hands upon her and strove to carry her away to his own dwelling. Ethne escaped from him, but the blaze of resentment at the insult that lit up in her soul consumed in her the fairy nature, that knows not of good or evil, and the nature of the children of Adam took its place. Thenceforth she ate not of the fairy food, which is prohibited to man, and she was nourished miraculously by the will of the One God. But after a time it chanced that Mananan and Angus brought from the Holy Land two cows whose milk could never run dry. In this milk there was nothing of the fairy spell, and Ethne lived upon it many long years, milking the cows herself, nor did her youth and beauty suffer any change.

Now it happened that on one very hot day the daughter of Mananan went down to bathe in the waters of the Boyne, and Ethne and her other maidens along with her. After they had refreshed themselves in the cool, amber-coloured water, they arrayed themselves in their silken robes and trooped back to the Brugh again; but ere they entered it, they discovered that Ethne was not among them.

So they went back, scattering themselves along the bank and searching in every quiet pool of the river and in every dark recess among the great trees that bordered it, for Ethne was dearly loved by all of them; but neither trace nor tidings of her could they find, and they went sorrowfully home without her, to tell the tale to Angus and to her father.

What had befallen Ethne was this. In taking off her garments by the riverside she had mislaid her fairy charm, and was become as a mortal maid. Nothing could she now see of her companions, and all around was strange to her. The fairy track that had led to the riverside was overgrown with briars, the palace of Angus was but a wooded hill. She knew not where she was, and pierced with sudden terror she fled wildly away, seeking for the familiar places that she had known in the fairy life, but which were now behind the Veil. At length she came to a high wall wherein was a wicket gate, and through it she saw a garden full of sweet herbs and flowers, which surrounded a steep-roofed building of stone. In the garden she saw a man in a long brown robe tied about his waist with a cord. He smiled at her and beckoned her to come in without fear. He was a monk of the holy Patrick, and the house was a convent church.

When the monk had heard her tale, he marvelled greatly and brought her to St Patrick himself, who instructed her in the Faith, and she believed and was baptized.