High in the Black Mountains of Carmarthenshire there is a small dark lake called Llyn y Fan Fach. It looks ordinary in daylight — cold, glacial, ringed by scree. But Welsh tradition holds that this is the lake that gave Wales one of its most beautiful and bittersweet love stories, and one of its most famous lines of healers.
A young farmer from the village of Blaensawdde took his cattle up to graze near the lake one morning, and there, sitting on the water as if it were dry stone, was the most beautiful woman he had ever seen. He offered her bread. She refused — it was too hard. He came back the next day with bread half-baked. She refused again — it was too soft. On the third day, he brought bread baked just right. She accepted, and agreed to marry him, on one condition: if he ever struck her three causeless blows, she would return to the lake forever.
She brought with her, as a dowry, a magnificent herd of fairy cattle that rose with her out of the water. They settled on a farm at Esgair Llaethdy. They had three sons. They were happy.
But over the years he tapped her — once at a christening when she wept, once at a wedding when she laughed, once at a funeral when she laughed again. Each time he meant nothing by it. Each time she warned him. On the third tap, she stood, called her cattle by name, and walked back into Llyn y Fan Fach. The herd followed her, and the lake closed over them.
Her sons were heartbroken. But the eldest, Rhiwallon, met her again at a place still called Llidiad y Meddygon — the Physicians' Gate. There, she taught him the healing properties of every herb that grew on the mountainside. He and his descendants became the Meddygon Myddfai — the Physicians of Myddfai — and their medical writings, copied through the medieval period, are among the oldest surviving medical texts in the Welsh language.
It is a story about loss that becomes a gift. About a love that ends and still leaves behind something the world needed. Stand at the edge of Llyn y Fan Fach on a still morning, and the surface really is glassy enough that you can almost believe a woman might walk out of it.