A NEW THEORY ON THE GODDESS CREIDDYLAD OF CULHWCH AND OLWEN

Altar to Gallia from Vindolanda/Chesterholm

Gwythyr, for whom Uther Pen appears to have fought, is linguistically the Welsh equivalent of Roman Victor.   However, as he is decidedly a Northern figure and is made to battle Gwyn son of Nudd, himself either a deity or a divine hero, there’s a good chance Gwythyr was substituted for the theonym Viteris or Veteres (and other variant spellings). This last was a very popular god along Hadrian’s Wall and the regions just to the north and south of the Wall during the Roman period.  

The Roman fort of Vindolanda, modern Chesterholm just south of Hadrian's Wall, has the second largest number of dedications to Viteris  Given that Vindo- means ‘white’ and is the British word that yielded the personal name Gwyn, I would hazard a guess that it was here that Gwythyr and Gwyn fought each other over Creiddylad.  

Creiddylad contains Welsh craidd, ‘center, middle, heart (GPC). She is a late reflection of the goddess Gallia of Vindolanda.  The dedication to Gallia reads:

CIVES GALLI
DE GALLIAE
CONCORDES
QUE BRITANNI

"The citizens of Gaul to the goddess Gallia, and the (citizens) of Britain in harmony, (dedicated this). [RIB3332]"

The word concordes means, literally, 'hearts together', from the assimilated form of com "with, together" (see con-) + cor (genitive cordis) "heart," from PIE root *kerd- "heart."

In other words, Concordes was at some point misunderstood and thought in the context of the dedication to be an epithet for Gallia.  This would have been easy to do, as there was a Roman goddess named Concordia. Thus, in a really strange way, Creiddylad = Gallia. Creiddylad is the daughter of Lludd, a Welsh variant of the Nudd who is Gwyn’s father.  Nudd, in turn, derives from the British theonym Nodens.

For more information on the altar to Gallia, see https://www.persee.fr/doc/antiq_0770-2817_2008_num_77_1_3718.

There are only a few extant inscriptions to Concordia in Britain (see https://romaninscriptionsofbritain.org/inscriptions/search?qv=concordia&submit=). The story about the ripping out of the heart of Cilydd son of Celyddon is a play on the Latin word discordia, "hearts apart", the opposite of concordia.