View source for Efnysien

==Role in Welsh tradition==
The Irish king [[Matholwch]] sails to [[Harlech]] to speak with [[Brân the Blessed]] high king of the [[Prydain|Island of the Mighty]] and to ask for the hand of his sister [[Branwen]] in marriage, thus forging an alliance between the two lands. Bendigeidfran agrees to Matholwch's request, but the celebrations are cut short when Efnysien, a half-brother to the children of [[Llŷr]], brutally mutilates Matholwch's horses, angry that his permission was not sought in regards to the marriage. Matholwch is deeply offended until Bran offers him compensation in the form of a magic [[Pair Dadeni|cauldron]] that can restore the dead to life. Pleased with the gift, Matholwch and Branwen sail back to Ireland to reign.

Once in Matholwch's kingdom, Branwen gives birth to a son, [[Gwern]], but Efnysien's insult continues to rankle among the Irish and, eventually, Branwen is mistreated, banished to the kitchen and beaten every day.  She tames a starling and sends it across the [[Irish Sea]] with a message to her brother Bran, who sails from Wales to Ireland to rescue her with his brother, [[Manawydan]] and a huge host of warriors, mustered from the 154 [[cantref]]s of Britain. The Irish offer to make peace and build a house big enough to entertain Bendigeidfrân but hang a hundred bags inside, supposedly containing flour but actually containing armed warriors. Efnisien, suspecting treachery, reconnoitres the hall and kills the warriors by crushing their skulls. Later, at the feast, Efnysien, again feeling insulted, murders Gwern by burning him alive, and, as a result, a vicious battle breaks out. Seeing that the Irish are using the cauldron to revive their dead, he  hides among the Irish corpses and is thrown into the cauldron by the unwitting enemy. He destroys the cauldron from within, sacrificing himself in the process.

Only seven men survive the conflict, among them [[Manawydan]], [[Taliesin]] and [[Pryderi]], prince of the [[Kingdom of Dyfed]], Branwen having herself died of a [[broken heart]]. The survivors are told by a mortally wounded Bran to cut off his head and to return it to Britain. For seven years the seven survivors stay in [[Harlech]], where they are entertained by Bendigeidfran's head, which continues to speak. They later move on to Gwales (often identified with [[Grassholm]] off Dyfed) where they live for eighty years without perceiving the passing of time. Eventually, Heilyn fab Gwyn opens the door of the hall facing Cornwall and the sorrow of what had befallen them returns. As instructed they take the now silent head to the Gwynfryn, the "White Hill" (thought to be the location where the [[Tower of London]] now stands), where they bury it facing France so as to ward off invasion.