Triffyn Farfog

King of Dyfed in the 4th century A.D. His heir was his son Aergol Lawhir, father of Vortiporius. 
He is the son of Aed Brosc, a Deisi invader from Ireland, of the dynasty of Eochaid Allmuir. 
Triffyn married Gwledyr, the heiress of the British kings of Dyfed, in the mid-5th century and inherited the kingdom. 
His fraternal nephew, Cormac mac Urb, was the grandfather of Brychan Brycheiniog, eponymous founder of Brycheiniog.
Also: Triffyn the Bearded