Saint Dyfrig, also known as Dubricius, was the first archbishop of Wales. The second name, of course, is a Latinization of the Welsh name. There doesn't seem to be much doubt of his historical work, having founded monasteries and held synods and such, but the legends are more fun. Yet the fun comes at the expense of overlooking the careful administration of the Church and cultivation of faith to which he dedicated his life. I guess that's what the sainthood's for -- to make up for the indignity of the legends.
His unwed mom was still pregnant with him when her father decided that her pregnancy warranted an execution. He was, after all, King Pepianus Clafrog of Ergyng (no doubt a mighty kingdom, at least the size of an average American college campus), and so high-born a man could not be expected bear such shame. He had her bagged up and thrown in the river, but she kept washing up on the bank. If you can't drown 'em, burn 'em, right? She was tossed into a roaring fire, but come the morning, she was sitting in the coals, hearty and hale, a newly delivered baby on her lap.
The King suffered from leprosy, and tended to foam at the mouth as well. This might be part of the reason he was so sensitive about matters of pride and shame. Anyway, the daughter and grandson were brought to him for further judgment, but young Dyfrig reached up, touched his grampy's foamy mouth, and healed him completely. Pepianus forgot all about his desire to kill his descendants, instead welcoming them into his home and adopting the grandson as heir. Whether the unnamed single mom also forgave and forgot seemed immaterial to the folks writing the story.
While serving as archbishop, he crowned King Arthur (according to Geoffrey of Monmouth). There's a tradition among Arthurian scholars suggesting that Arthur's mentor Merlin was the same guy as Dubricius (also called Ambrosius). Whether or not you want to go that far, he shows up in Tennyson's Idylls of the King, so he's got a place in Camelot whether or not Lerner and Loewe put him in the show.
He was known as a wise counselor, administrator, and healer during his forty-three years of service as a bishop. Unlike folks who stay in office past their effectiveness, he retired to a hermitage after endorsing St. David (patron of Wales) as his successor. When he finally died, his relics were eventually washed before being places in a reliquary. It was said that the water was heated by some, while in another basin, an arm bone moved by itself for an hour or so.