It is said that long ago a Kellish bard named Llewellyn won the heart of a beautiful mermaid. The mermaid asked her mother Mhorann (a powerful sorceress) if she could wed the Kell, and live with him in his keep on land. Mhorann denied the request and forbade her daughter to ever see Llewellyn again. Desperate and confused the young mermaid sought out the sorcerer Math Mathonwy to aid her. The sorcerer agreed to help the mermaid, but warned her that what she wanted could not be undone. The mermaid agreed, and Math Mathonwy cast the spell to make her human and hide her from her mother’s gaze. The young woman then sought out Llewellyn so that they might begin their lives together. But when Llewellyn saw her, he recoiled in disgust, as Math Mathonwy’s spells had left her plain and uncomely.
Spurned by Llewellyn, the heartbroken maid returned to Math Mathonwy and begged him to undo his sorceries, but he would not. She then ventured back to the sea shore, where she found some of her sisters sitting on rocks and singing. She pleaded with them to help her, but they could not see her. Lost and without hope she then climbed a great cliff and threw herself off, landing on the rocks near her sisters. As her last breath left her body, Math Mathonwy’s spells were undone, and her sisters again saw her. When her body was returned to her mother, Mhorann set a curse upon Llewellyn and all Kells, that should they cross the open sea, Mhorann would have her vengeance. From that day forth, all Kells who leave the sight of land are attacked by great sea creatures or murderous storms. As a result, Kells do not leave the sight of land.