Wikipedia entry for: Einion ap Cunedda (c. 420-500; reigned from the 470s) (Latin: Engenius), also known as Einion Yrth ('the Impetuous') was a king of Gwynedd.
One of the sons of Cunedda, it is believed he traveled with his father to North Wales in the early 450s to expel Irish raiders from the region. After his father's death, Einion inherited control over the newly founded kingdom of Gwynedd. Aided by his brother Ceredig, ruler of Ceredigion, and his nephew Meirion, ruler of Meirionnydd, Einion built upon his father's successes and further established his family's rule in the region. He was succeeded by two sons; Cadwallon Lawhir and Owain Ddantgwyn.
Death
Date: 460
Place: Gwynedd, Wales
Issue
Cadwallon Lawhir m. Meddyf ferch Maeldaf ap Dylan Draws of Nanconwy [1]
↑ 1.01.11.21.31.41.51.6 Carl Boyer 3rd. Medieval Welsh Ancestors of Certain Americans. Generally follows Bartrum. By the author: Santa Clarita, California, 2004. Einion Yrth is #3 on page 68.