7th c. Saint of Anglesey, Wales. Also called Nidan. Evangelist. Other details of his life are unknown.
Wales seems to have a large number of saints who are only known because an ancient church is named after them however the history of Christianity and the saints in Wales is rich and deep.
More information on Welsh saints:
The Age of Saints in Wales – Britain Express
The Age of Saints – Castle Wales
The Saints of North Wales – Noel Walley