Gwydion tricked his sister into giving his nephew Lleu Llaw Gyffes a name and a weapon, and saved him from his scheming wife Blodeuwedd.
Gwydion fathered children with his brother Gilfaethwy after they were transformed into three different pairs of mating animals as a punishment.
While he was both wise and powerful, Gwydion was never a ruler himself, preferring to serve as an advisor to his nephew, who was king.
Gwydion fab Dôn was the great magician and trickster of the Fourth Branch of the Welsh Mabinogi. The Lord of Caer Wydion, he was the uncle of Lleu Llaw Gyffes and brother of Lleu’s mother Arianrhod, with whom he often quarreled. His character, like his magic, ranged from benevolent to villainous.
The name Gwydion, rendered in Modern Welsh as Gwyddien, could have meant “born of the Trees.” His surname, fab Dôn, simply meant “son of Dôn,” and referred to his maternal lineage.
A cunning and skilled magician, Gwydion was able to use magic to enhance his own abilities and change the forms of others. While his chief attribute was his deft mind, he was also a capable warrior strong enough to defeat one of Wales’ most powerful lords in single combat. According to medieval Welsh poetry, his magic could create women out of flowers and test the sexual purity of women such as his sister.
Though he was a trickster, Gwydion possessed a strong sense of loyalty to certain members of his family, most notably his nephew Lleu.
Gwydion had a number of locations associated with him, including the Milky Way; in Welsh, our galaxy is named after his castle, Caer Wydion. He was said to be buried in Dinas Dinlle, the city of Lleu.
As the son of the often-mentioned yet largely mysterious Dôn, Gwydion had a number of siblings, including brothers Gilfaethwy and Amatheon and sister Arianrhod. His extended family included his uncle, Math fab Mathonwy, king of Gwynedd, and his nephews Dylan and Lleu. Via a punishment imposed by his uncle, Gwydion and Gilfaethwy became the parents of three brothers: Hyddwn, Hychdwn, and Bleiddwn. All three children were raised by Math.
Gwydion was a major character in the Fourth Branch of the Mabinogi.
#Fourth Branch of the Mabinogi
Gwydion himself was the best bard in the world. And that night he delighted the court with entertaining recitals and story-telling, until he was feted by the whole court, and it was with pleasure that Pryderi conversed with him.
Fourth branch of the Mabinogi
The War with Pryderi
In his most famous legend, Gwydion started a war with Math’s rival Pryderi to help his brother Gilfaethwy satisfy his sexual desires for Goewin, his uncle’s foot-holder. Gwydion initiated the conflict by stealing the otherworldly pigs of Pryderi, and later ended it by defeating Pryderi in single combat. Gwydion’s victory enabled his uncle to drastically expand the borders of his kingdom.
Upon discovering Gilfaethwy’s rape of Goewin, Math punished Gilfaethwy and Gwydion by turning them into mating animals. In turn, the two brothers were transformed into elk, cows, and wolves. During the course of each transformation, Gilfaethwy was forced to bear a child. Math took the three children and raised them himself. Following this punishment, Gwydion suggested that his sister Arianrhod serve as Math’s new foot-holder and used his magic to prove her purity. During this test, however, Arianrhod gave birth to a boy, Dylan. Through this act Arianrhod demonstrated her lack of purity, and she fled in shame. During her flight, Arianrhod dropped a bundle that was retrieved by Gwydion. In the morning, he discovered that the bundle was actually a second child—a nameless boy. Arianrhod had cursed the boy so no one could name him, save her.
The Curses of Arianrhod
Some years later, Gwydion and the unnamed boy journeyed to Caer Arianrhod in order to undergo a series of trials. Once there, a disguised Gwydion tricked Arianrhod into naming the boy Lleu Llaw Gyffes, meaning “the fair-haired one with the skilled hands.” Angered by this deception, she cursed Lleu again, this time proclaiming he could receive no weapon lest it be from her. However, Gwydion managed to outsmart her once more. Arianrhod cursed Lleu a final time, stating he would never marry a human woman. In response, Gwydion summoned a woman made of flowers, baptized her, and named her Blodeuwedd. Using magic and his clever mind, Gwydion thrice defied Arianrhod and her curses.
Ultimately, Blodeuwedd proved a poor wife for Lleu and soon began plotting his demise. Gwydion overcame Blodeuwedd’s plans by healing his nephew’s wounds and turning her into an owl, the most hated of all birds. Following these events, Gwydion served as advisor to Lleu when he ascended to the throne of Gwynedd.
#Battle of the Trees
In The Book of Taliesin, Gwydion, his brother Amatheon, and their nephew Lleu faced down the Lord of Annwn, having stolen a deer and a puppy from him. The battle of magical wits ended with a riddle, whereby the Lord of Annwn could only be defeated if Gwydion could guess his name. After recognizing a symbol on his shield, Gwydion named his adversary as Arawn, Lord of Annwn, thereby guessing correctly and vanquishing his foe.
Gwydion’s role as magical advisor to Lleu is not unlike the Irish Dagda’s role as chief advisor to Lugh and other kings. This similarity is significant, given that Lleu and Lugh are geographically distinct versions of the same Celtic god, who also appears as “Luggus” in Gaul’s version of the mythos.
Gwydion also bore similarities to the Arthurian Merlin, both in using trickery to allow his brother to lay with a woman (not unlike Uther Pendragon and Igraine) and in being able to change forms, albeit sometimes against his will. Despite these passing similarities, the two beings had markedly different personalities. For example, Gwydion was consistently shown to be more of a trickster than Merlin.
Gwydion has appeared across a number of works in popular culture:
In Lloyd Alexander’s The Chronicles of Prydain, Gwydion’s character was much more noble. By the series’ end he was recast as the High King of Prydain, though his war with Arawn formed the premise for the entire series;
The Keltiad series by Patricia Kennealy-Morrison cast Gwydion as one of its protagonists. In the series he was married to the Queen of Keltia, Aeron Aoibhell;
In Neil Gaiman’s American Gods, he appeared briefly as a stock boy;
In Marion Zimmer Bradley’s The Mists of Avalon, the birth name of Arthur was Gwydion. The name Gwydion also appeared as the birth name of Arthur’s son via half-sister Morgaine. Later, Arthur’s son took the name Mordred.
The Portuguese folk metal band Gwydion derived their name from the character, and have referenced both Viking and Celtic mythology in their lyrics.