Questions to consider . . .
You can find both of the papers quoted linked below. The first by Proinsias Mac Cana is an important paper in Celtic Mythology, but it is a little dry, the second is an easier read.
Notes and References
Rhiannon the Goddess:
This is how the hag was: every joint and limb of her from top to toe as black as coal. The gray bristly hair growing through the top of her head was like the tail of a wild horse. She could cut off the green branch of an acorn-bearing oak with the sickle of green teeth that was in her head, reaching to her ear. Her eyes were black and smoky; her nose crooked and wide-nostrilled; her belly sinewy, speckled, fluxy, diseased; her shins crooked, twisted, knotty, broad as shovels; and she had big knees and gray nails. Fearsome was the appearance of the hag.
‘There is a stag-hound bitch here,’ she said, ‘and she has pups. Let us kill some of the pups, and smear Rhiannon’s face and hands with the blood, and throw the bones beside her, and swear that she herself destroyed her son. And the word of the six of us will prove stronger than hers.’
The idea of the goddess changing her form and her raiment when she is without her proper spouse and king, is very common in the whole of our literature — its best known forms is that of the ugly old hag who, on union with the rightful aspirant to the kingship of Ireland, immediately becomes a beautiful woman.
. . . there are problems inherent in an undisputed application of this methodology. Rhiannon must also be regarded as a literary character and not simply the remnant of a degenerated goddess. . . . For example, in Proinsias Mac Cana’s reading of Rhiannon, he questions her behavior in the Third Branch of thee Mabinogi as incompatible with her goddess feature. Pryderi is stuck to a golden bowl and is about to be abducted by an unseen enemy. Although Manawydan, Pryderi’s friend and Rhiannon’s husband, makes no effort to rescue him, Rhiannon makes an attempt but is stolen herself.
. . . According to Mac Cana, this impetuous behavior reveals a character flaw in Rhiannon, contradicting her supposed divine nature. The flaw in her character resides in her loss of wisdom and judgment and Manawydan is commended for his caution and prudence.
However, the behavioral inconsistency described by Mac Cana exists only if Rhiannon is defined through the realm of a goddess; it is perfectly explainable through mortal behavior. As a mother, there is neither anything odd nor impulsive about her reaction to save her son. By explaining her role as Mac Cana has done only through her divinity, we neglect a depth of character that prohibits Rhiannon’s interpretation as a multifaceted character.
Rhiannon the mortal woman:
Can she be both?