|Gwyllyw and Gladys|
King Arthur has a supporting role in the Life of Saint Cadoc. Arthur took a shine to Sweet Gladys and considered abducting her for himself. His step-brother and seneschal, [Sir] Cai[us], persuaded Arthur to pass on the princess. Then, when the battle between Gwyllyw and Brychan (and their small armies) is deadlocked, Arthur, Cai, and Bedywyr ride in and tip the balance in favor of the gallant young bandit prince. Had Arthur not listened to Cai, he might never have married Guinevere, Lanzlot might never have betrayed his King's trust, and Camelot would not have fallen. The Romano-Celtic kingdoms of Britain would not have been overrun by Saxons, nor perhaps by Normans, and the whole course of western... you get the idea.
In the Life of Saint Cadoc, Gladys gets a little credit for turning her husband from a life of crime, though the bulk of the credit goes to Cadoc himself. I prefer to imagine that Gwyllyw and Gladys are shoulder-to-shoulder against all Wales, tearing it up and having a great time until their kids call them to their senses. Anyway, there's common agreement that they quit their evil ways and built a hermitage together until their celibate cohabitation became too much. Gladys moved away and built her own hermitage at Pencarn, in Bassaleg. There are several places in the area where she is said to have lived or bathed (how suggestive!), or that are just dedicated to her.