Cadoc of Tabriol
On Erec's third day of adventuring with his wife to prove his prowess, they met Sir Cadoc's lady weeping because two giants had just captured her lover. Erec gave pursuit and found Cadoc, naked, bound, and perched on a nag, his captors beating him with scourges until the blood ran.
Erec challenged, battled, and killed both giants, armed though they were with great, iron-shod clubs. Then he gave the grateful Cadoc back to his lady, requesting them to take the story to King Arthur, which they did. If the usual pattern holds, Cadoc and his lady would have joined Arthur's court.
He is called Kalviel in the Norse Erex Saga.
The Welsh saint was supposed to be the son of King Gwynnlym of Glamorgan and Saint Gwladys of Brecon.
Cadoc’s father, Gwynnlym, was harbored by Arthur when he kidnapped the lady Gwladys from her husband. Years later, Cadoc, the Abbot of Llancarfan, harbored a fugitive named Ligessauc (Ligessac) who had killed three of Arthur’s knights.
After seven years, Cadoc was finally able to make Arthur accept a payment of a hundred kine (cattle) for the lives of the three knights. Arthur agreed, but demanded that every cow had to be half-red and half-white. Cadoc, through holy means, transformed the cows into such colors, but the cows later turned into ferns. Arthur, humbled through the experience, named the location Ferntown.