St Cadoc is a 5th Century saint and martyr who founded a monastery at Llancarfan, near Cowbridge, Glamorgan, Wales. Son of a robber King, he learnt his Latin under an Irish priest. His story is not written down until the 11th Century, but he has associations with Scotland, Brittany as well as Wales. His story brings him into conflict with King Arthur, who demanded compensation after he sheltered a man who had killed three of Arthur’s men.
The Catholic Church celebrates him in September, elsewhere on the 24th January.
For more look at https://celticsaints.org