Their son converted the raider king she had married — and then had to separate them.
Daughter of King Brychan of Brycheiniog, she married Gwynllyw, king of Gwynllŵg, in circumstances the two Welsh Lives tell in opposite ways: one makes it a peaceful marriage, the other an armed abduction in which King Arthur himself, with Cai and Bedwyr, is said to have taken the ravisher’s side. Gwynllyw was a warrior and a cattle raider. It was their son Cadoc, who would become abbot of Llancarfan and one of the most venerated of Welsh saints, whose example and preaching obtained his conversion. A vision decided him to withdraw to the hill where Newport cathedral now stands, and Gwladys followed him into the eremitic life: fasts, a meatless diet, bathing in the cold water of the Usk. They led it together, and too closely: their own son came to reprove them and required that they move apart. She then settled alone at Pencarn, near Bassaleg, and afterwards higher up at Gelligaer, where the foundations of a chapel still bear her name. She is kept with her husband on 29 March, and her principal church is now at Bargoed.
A queen in penitential dress, her crown laid aside. Her iconography is modern and Welsh: a stained-glass window in St Martin’s church at Caerphilly depicts her.