The king of Cornouaille, Gradlon, had many ships which he used to wage war against the far away countries of the North. An outstanding strategist, he won most of the battles and pillaged the vanquished, thereby amassing great wealth.
But one day, his sailors tired of all this fighting, and refused to continue to lay siege to a particular castle. The king left Cornouaille, exiling himself to the North. Once while walking alone, he saw the red-headed woman Malgven, the Queen of the North, who was standing in front of him. She told him: "I know you; you are courageous and skillful in fighting. My husband is old, his sword was rusted. You and I are going to kill him. Then we shall return to your country of Cornouaille." They killed the king of the North and rode on Morvarc'h ("sea horse" in Breton), the Malgven magical horse. It was black, spit fire from its nostrils and was able to gallop on the sea. They caught up with Gradlon's vessels, but the approach of Morvarc'h caused the fleet to flee.
Gradlon and Malgven remained long at sea, so Malgven gave birth to a daughter, Dahut. According to some versions of the story, it killed the queen. According to other versions, she did not die, but some time after the birth of Dahut, she asked Gradlon what he thought about Dahut. He responded, "I already cherish her as I cherish you."
Malgven announced that Dahut's face would keep the appearance of hers, so she would not be forgotten by him, because it was time for her to return to her world. She added that they would see an island shortly after, and Gradlon should let her go there; otherwise they could never see the earth again. Soon after, they saw an island and there Malgven was left alone. Shortly after, Gradlon arrived in Cornouaille with Dahut, but without Malgven.
The legend of Ys
Dahut had a key role in the legend of Ys.
Mark of Cornwall
In a Breton legend, Mark of Cornwall is also the king of Cornouaille, where, one day, he hunted a doe before discovering she was, actually, the princess Dahut. Dahut, under her human appearance, condemned him to have the ears and the mane of his horse Morvarc'h.
According to a legend, the city of Carhaix was founded by Dahut, a reference to a supposed Breton language etymology "Ker Ahes" (city of Ahes).
References in the arts
French singer Nolwenn Leroy recorded a song titled "Ahès" on her 2012 album Ô Filles de l'Eau.
Meurtres en Cornouailles https://fr.m.wikipedia.org/wiki/Meurtres_en_Cornouaille