One day some moist bread from the lake came floating ashore. The farmer seized it, and devoured it with avidity. The following day, to his great delight, he was successful in his chase, and caught the nymphs on the shore. After talking a long time with them, he mustered up the courage to propose marriage to one of them. She consented to accept him on condition that he would distinguish her from her sisters the next day. This was a new and great difficulty to the young farmer, for the damsels were so similar in form and features, that he could scarcely see any difference between them. He noted, however, a trifling singularity in the strapping of the chosen one's sandal, by which he recognized her on the following day. As good as her word, the gwraig immediately left the lake and went with him to his farm. Before she quitted the lake she summoned therefrom to attend her, seven cows, two oxen, and one bull. She stipulated that she should remain with the farmer only until such time as he should strike her thrice without cause. For some years they dwelt peaceably together, and she bore him three sons, who were the celebrated Meddygon Myddfai. One day, when preparing for a fair in the neighbourhood, the farmer desired her to go to the field for his horse. She said she would, but being rather dilatory, he said to her humorously 'Dôs, dôs, dôs,' i.e., 'Go, go, go,' and at the same time slightly tapped her arm three times with his glove.... The blows were slight--but they were blows. The terms of the marriage contract were broken, and the dame departed, summoning with her her seven cows, her two oxen, and the bull. The oxen were at that moment ploughing in the field, but they immediately obeyed her call and dragged the plough after them to the lake. The furrow, from the field in which they were ploughing to the margin of the lake, is still to be seen--in several parts of that country--at the present day. After her departure, the gwraig annwn once met her three sons in the valley now called Cwm Meddygon, and gave them a magic box containing remedies of wonderful power, through whose use they became celebrated. Their names were Cadogan, Gruffydd and Einion, and the farmer's name was Rhiwallon. Rhiwallon and his sons, named as above, were physicians to Rhys Gryg, Lord of Dynevor, and son of the last native prince of Wales. They lived about 1230, and dying, left behind them a compendium of their medical practice. 'A copy of their works is in the Welsh School Library in Gray's Inn Lane.'[26]