Einion Frenin

A Welsh confessor and saint of the Celtic Church. 
Son of Owain Ddantgwyn, and the brother of Cuneglasus, King of Rhos, and of the saints Seiriol and Meirion. As part of Gwynedd's Cuneddan dynasty, known as "Saint Einion the King", he did rule as a prince (Latin: regulus) in the Llŷn Peninsula. 
Also: Saint Einion Frenin