Mererid (‘Pearl’) is named as a ‘fountain cup-bearer’ in a medieval Welsh poem in The Black Book of Carmarthen. The poem refers to the story of the drowning of the lands known as Cantre’r Gwaelod in Cardigan Bay on the west coast of Wales. This story predates the later and more well-known version which blames the drowning of the land on the drunkenness of Seithennin who leaves open the sluice gates to allow the water in. But in the earlier story Seithennin’s role is more ambiguous as he hears Mererid’s cry ringing out over the fortress as the waters rise.
The Celtic scholar and folklorist John Rhŷs thought that Mererid was the keeper of a ‘fairy well’, the waters from which, implicitly from the Otherworld, rose up to flood the land. Why? This site offers some exploration of the possible answers to that question and the identity of Mererid and also provides both direct links to similar well legends and further indirect links to stories of water nymphs, rivers, streams and other sacred waters.