Here is the story of the Lady of the Lake of Llyn y Fan Fach as related by John Rhŷs in Celtic Folklore, published in 1901.
There lived at Blaensawdde near Llanddeusant, Carmarthenshire, a widowed woman who had an only son to bring up. She sent a portion of her cattle to graze on the adjoining Black Mountain, and their most favourite place was near the small lake called Llyn y Fan Fach, on the north-western side of the Carmarthenshire Fans.
The son was generally sent by his mother to look after the cattle on the mountain. One day, along the margin of the lake, to his great astonishment, he beheld, sitting on the unruffled surface of the water, a lady; one of the most beautiful creatures that mortal eyes ever beheld, her hair flowed gracefully in ringlets over her shoulders, the tresses of which she arranged with a comb, whilst the glassy surface of her watery couch served for the purpose of a mirror, reflecting back her own image. Suddenly she beheld the young man standing on the brink of the lake, with his eyes riveted on her, and unconsciously offering to herself the provision of barley bread and cheese with which he had been provided when he left his home.
Bewildered by a feeling of love and admiration for the object before him, he continued to hold out his hand towards the lady, who imperceptibly glided near to him, but gently refused the offer of his provisions. He attempted to touch her, but she eluded his grasp, saying--
Cras dy fara; Nid hawdd fy nala.
Hard baked is thy bread! 'Tis not easy to catch me
and immediately dived under the water and disappeared, leaving the love-stricken youth to return home, a prey to disappointment and regret that he had been unable to make further acquaintance with one, in comparison with whom the whole of the fair maidens of Llanddeusant and Myddfai whom he had ever seen were as nothing.
On his return home the young man communicated to his mother the extraordinary vision he had beheld. She advised him to take some unbaked dough or "toes" the next time in his pocket, as there must have been some spell connected with the hard-baked bread, or "Bara cras," which prevented his catching the lady.
Next morning, before the sun had gilded with its rays the peaks of the Fans, the young man was at the lake, not for the purpose of looking after his mother's cattle, but seeking for the same enchanting vision he had witnessed the day before; but all in vain did he anxiously strain his eyeballs and glance over the surface of the lake, as only the ripples occasioned by a stiff breeze met his view, and a cloud hung heavily on the summit of the Fan, which imparted an additional gloom to his already distracted mind.
Hours passed on, the wind was hushed, and the clouds which had enveloped the mountain had vanished into thin air before the powerful beams of the sun, when the youth was startled by seeing some of his mother's cattle on the precipitous side of the acclivity, nearly on the opposite side of the lake. His duty impelled him to attempt to rescue them from their perilous position, for which purpose he was hastening away, when, to his inexpressible delight, the object of his search again appeared to him as before, and seemed much more beautiful than when he first beheld her. His hand was again held out to her, full of unbaked bread, which he offered with an urgent proffer of his heart also, and vows of eternal attachment. All of which were refused by her, saying-
Llaith dy fara! Ti ni fynna'.
Unbaked is thy bread! I will not have thee
But the smiles that played upon her features as the lady vanished beneath the waters raised within the young man a hope that forbade him to despair by her refusal of him, and the recollection of which cheered him on his way home. His aged parent was made acquainted with his ill-success, and she suggested that his bread should next time be but slightly baked, as most likely to please the mysterious being of whom he had become enamoured.
Impelled by an irresistible feeling, the youth left his mother's house early next morning, and with rapid steps he passed over the mountain. He was soon near the margin of the lake, and with all the impatience of an ardent lover did he wait with a feverish anxiety for the reappearance of the mysterious lady.
The freshness of the early morning had disappeared before the sultry rays of the noon-day sun, which in its turn was fast verging towards the west as the evening was dying away and making room for the shades of night, and hope had well-nigh abated of beholding once more the Lady of the Lake. The young man cast a sad and last farewell look over the waters, and, to his astonishment, beheld several cows walking along its surface. The sight of these animals caused hope to revive that they would be followed by another object far more pleasing; nor was he disappointed, for the maiden reappeared, and to his enraptured sight, even lovelier than ever. She approached the land, and he rushed to meet her in the water. A smile encouraged him to seize her hand; neither did she refuse the moderately baked bread he offered her; and after some persuasion she consented to become his bride, on condition that they should only live together until she received from him three blows without a cause,
Tri ergyá diachos. Three causeless blows.
And if he ever should happen to strike her three such blows she would leave him forever. To such conditions he readily consented, and would have consented to any other stipulation, had it been proposed, as he was only intent on then securing such a lovely creature for his wife.
Thus the Lady of the Lake engaged to become the young man's wife, and having loosed her hand for a moment she darted away and dived into the lake. His chagrin and grief were such that he determined to cast himself headlong into the deepest water, so as to end his life in the element that had contained in its unfathomed, depths the only one for whom he cared to live on earth. As he was on the point of committing this rash act, there emerged out of the lake two most beautiful ladies, accompanied by a hoary-headed man of noble mien and extraordinary stature, but having otherwise all the force and strength of youth. This man addressed the almost bewildered youth in accents calculated to soothe his troubled mind, saying that as he proposed to marry one of his daughters, he consented to the union, provided the young man could distinguish which of the two ladies before him was the object of his affections. This was no easy task, as the maidens were such perfect counterparts of each other that it seemed quite impossible for him to choose his bride, and if perchance he fixed upon the wrong one all would be forever lost.
Whilst the young man narrowly scanned the two ladies, he could not perceive the least difference betwixt the two, and was almost giving up the task in despair, when one of them thrust her foot a slight degree forward. The motion, simple as it was, did not escape the observation of the youth, and he discovered a trifling variation in the mode with which their sandals were tied. This at once put an end to the dilemma, for he, who had on previous occasions been so taken up with the general appearance of the Lady of the Lake, had also noticed the beauty of her feet and ankles, and on now recognizing the peculiarity of her shoe-tie he boldly took hold of her hand.
"Thou hast chosen rightly," said her father; "be to her a kind and faithful husband, and I will give her, as a dowry, as many sheep, cattle, goats, and horses as she can count of each without heaving or drawing in her breath. But remember, that if you prove unkind to her at any time, and strike her three times without a cause, she shall return to me, and shall bring all her stock back with her."
Such was the verbal marriage settlement, to which the young man gladly assented, and his bride was desired to count the number of sheep she was to have. She immediately adopted the mode of counting by fives, thus:--One, two, three, four, five -- One, two, three, four, five; as many times as possible in rapid succession, till her breath was exhausted. The same process of reckoning had to determine the number of goats, cattle, and horses respectively; and in an instant the full number of each came out of the lake when called upon by the father.
The young couple were then married, by what ceremony was not stated, and afterwards went to reside at a farm called Esgair Llaethdy, somewhat more than a mile from the village of Myddfai, where they lived in prosperity and happiness for several years, and became the parents of three sons, who were beautiful children.
Once upon a time there was a christening to take place in the neighbourhood, to which the parents were specially invited. When the day arrived the wife appeared very reluctant to attend the christening, alleging that the distance was too great for her to walk. Her husband told her to fetch one of the horses which were grazing in an adjoining field. "I will," said she, "if you will bring me my gloves which I left in our house." He went to the house and returned with the gloves, and finding that she had not gone for the horse jocularly slapped her shoulder with one of them, saying, "go! go!", when she reminded him of the understanding upon which she consented to marry him:-That he was not to strike her without a cause; and warned him to be more cautious for the future.
On another occasion, when they were together at a wedding, in the midst of the mirth and hilarity of the assembled guests, who had gathered together from all the surrounding country, she burst into tears and sobbed most piteously. Her husband touched her on her shoulder and inquired the cause of her weeping: she said, "Now people are entering into trouble, and your troubles are likely to commence, as you have the second time stricken me without a cause."
Years passed on, and their children had grown up, and were particularly clever young men. In the midst of so many worldly blessings at home the husband almost forgot that there remained only one causeless blow to be given to destroy the whole of his prosperity. Still he was watchful lest any trivial occurrence should take place which his wife must regard as a breach of their marriage contract. She told him, as her affection for him was unabated, to be careful that he would not, through some inadvertence, give the last and only blow, which, by an unalterable destiny, over which she had no control, would separate them for ever.
It, however, so happened that one day they were together at a funeral, where, in the midst of the mourning and grief at the house of the deceased, she appeared in the highest and gayest spirits, and indulged in immoderate fits of laughter, which so shocked her husband that he touched her, saying, "Hush! hush! don't laugh." She said that she laughed "because people when they die go out of trouble," and, rising up, she went out of the house, saying, "The last blow has been struck, our marriage contract is broken, and at an end! Farewell!" Then she started off towards Esgair Llaethdy, where she called her cattle and other stock together, each by name. The cattle she called thus:--
Mu wlfrech, Moelfrech, Mu olfrech, Gwynfrech, Pedair cae tonn-frech, Yr hen wynebwen. A'r las Geigen, Gyda'r Tarw Gwyn O lys y Brenin; A'r llo du bach, Syll ar y bach, Dere dithau, yn iach adre!
Brindled cow, white speckled, Spotted cow, bold freckled, The four field sward mottled, The old white-faced, And the grey Geingen, With the white Bull, From the court of the King; And the little black calf Tho' suspended on the hook, Come thou also, quite well home!
They all immediately obeyed the summons of their mistress. The "little black calf," although it had been slaughtered, became alive again, and walked off with the rest of the stock at the command of the lady. This happened in the spring of the year, and there were four oxen ploughing in one of the fields; to these she cried:--
Pedwar eidion glas /Sydd ar y maes, /Deuwch chwithau /Yn iach adre!
The four grey oxen, /That are on the field, /Come you also /Quite well home!
Away the whole of the live stock went with the Lady across Myddfai Mountain, towards the lake from whence they came, a distance of above six miles, where they disappeared beneath its waters, leaving no trace behind except a well-marked furrow, which was made by the plough the oxen drew after them into the lake, and which remains to this day as a testimony to the truth of this story.
What became of the affrighted ploughman--whether he was left on the field when the oxen set off, or whether he followed them to the lake, has not been handed down to tradition; neither has the fate of the disconsolate and half-ruined husband been kept in remembrance. But of the sons it is stated that they often wandered about the lake and its vicinity, hoping that their mother might be permitted to visit the face of the earth once more, as they had been apprised of her mysterious origin, her first appearance to their father, and the untoward circumstances which so unhappily deprived them of her maternal care.
In one of their rambles, at a place near Dôl Howel, at the Mountain Gate, still called "Llidiad y Meddygon," The Physicians' Gate, the mother appeared suddenly, and accosted her eldest son, whose name was Rhiwallon, and told him that his mission on earth was to be a benefactor to mankind by relieving them from pain and misery, through healing all manner of their diseases; for which purpose she furnished him with a bag full of medical prescriptions and instructions for the preservation of health. That by strict attention thereto he and his family would become for many generations the most skilful physicians in the country. Then, promising to meet him when her counsel was most needed, she vanished. But on several occasions she met her sons near the banks of the lake, and once she even accompanied them on their return home as far as a place still called "Pant-y-Meddygon," The dingle of the Physicians, where she pointed out to them the various plants and herbs which grew in the dingle, and revealed to them their medicinal qualities or virtues; and the knowledge she imparted to them.