Edeyrn, Edyrn, Isedernus

An Arthurian warrior in Welsh legend who was the son of Nudd, hence brother of Gwynn ap Nudd.

He was the leader of Arthur's Danish warriors and was Geraint's opponent in the Knight of the Kestrel tournament.

Edern appears in French literature as Yder. Like Gwynn his character is identical to a Romano-British deity, Aeternus. He appears more often in the traditions on the Continent than the British. In The Dream of Rhonabwy he leads a Danish sable troop through Rhonabwy's dream and he is Arthur's advisor. In Erec and Enide he is called Yder fiz Nut.

He is depicted on the Modena archivolt in Italy, there called Isedernus.

See also
Culhwch | The Legend of King Arthur