This is one of a number of tales that are found across Wales, in which a fairy lady agrees to marry a young man on one condition; when this condition is broken, she leaves her family, and returns to fairy land.
This legend dates from about the thirteenth century. But myths of this type go back much further. The first recorded Welsh myth of a meeting with the fairies was written down in 1181 (in the Giraldus Cambrensis).
However, this story is very similar to an ancient Hindu Folk tale. This has led people to believe that the myths are related and, therefore, the roots are very old indeed, going back to a time before the Celts travelled to Europe and Wales.
In both the Welsh and Hindu tale, a young man is entranced by a fairy lady from a lake who tells him, 'I am hard to be caught' (in welsh: Nid hawdd fy nala). In both cases, the immortal fairy weds the mortal, conditionally, and for a while they are happy, then unwittingly, the prohibited thing is done, and the lady vanishes away.
Who were the fairy people?
A Lake Fairy
The fairies in the Welsh tales are different from fairies as we think of them today. Although the Welsh do have a small type of elf or goblin - the Ellyll, the fairies described in stories, such as this one, are spoken of as people not goblins.
They are known as "Y Tylwyth Teg," or 'the Fair Tribe' and are about the same size as humans. They have the same needs and concerns as human beings and, in many tales, marry humans, although the fairies themselves are often immortal (that is they live for ever).
The descriptions in these stories has led some people to think that the stories are based on a race of people that actually existed, and were largely driven out by the Celts when the arrived, so that they existed only in the more remote areas. The myths, therefore, were based on a memory of these people, who, over time became the fairies.
Why did the Fairy come from the lake?
The Black Mountain
Many myths and folk tales in Wales are associated with lakes. In many Fairy stories lakes seem to provide an entrance to the Fairies' kingdom. Fairy ladies emerge from lakes and disappear into lakes.
In several old stories there is more than one world. There are, for example, the world of people, the underworld or world of the dead (sometimes heaven and hell) and a third kingdom, that of the fairies or immortals.
Many tales involving women coming from lakes have Celtic origins. Lakes were thought to provide a link between the world of the living and the world of the dead; perhaps they were also thought to provide a link to the third or 'fairy kingdom'.
Other people have suggested that maybe, at one time, there were people who made their homes on the lake or 'lake-dwellers'. In some countries, the remains of lake villages belonging to the Stone Age, and even to the Bronze Age, have been discovered, with houses built on stilts. In some lakes, including Lake Bala in Wales, there are legends of old towns buried beneath the waters. The legends may be linked with distant memories of such people.
Is there any truth in the tale?
The Meddygon Myddvai
Rhiwallon and his sons, Cadwgan, Gruffydd, and Einion actually existed and were known as the Meddygon Myddvai.
They were the chief physicians of their age, and they wrote down their knowledge in their 'treatise on medicine' in the Red Book of Hergest. A copy of their works is in the Welsh School Library, in Gray's Inn Lane.
There is some dispute about the date of their writings . The author of an old book - the 'Cambro-Briton' dates them to 1230 A.D. However, the editor of that publication speaks of a manuscript written by these physicians about the year 1300. Modern experts think that the writings date to the end of the fourteenth century, about 1380 to 1400.
They are also described as Physicians of Rhys Gryg, a prince of South Wales, who lived in the early part of the thirteenth century. Therefore, the events in the story would date to the thirteenth, or at the latest, the fourteenth century.
They were great and famous men of their time. Certainly a mothers love is strong and any parent separated from their children would want to maintain contact with them.
However, whether their knowledge was passed on down the generations and built up over time, or given by a mother that belonged to the Fairy Kingdom, can never be proved.