A member of the House of Aberffraw, he inherited the throne from his father, Anarawd ap Rhodri.
[1] Idwal inherited the throne of Gwynedd on the death of his father Anarawd ap Rhodri in 916.
As Æthelstan was eager to establish his authority across Britain, Idwal honoured him by visiting the English court in 927, 928 and 937.
The Annales Cambriæ record his failure: "Idwal and his brother Elisedd are killed in battle against the Saxons".
The throne of Gwynedd should have passed to Idwal's sons Iago and Ieuaf, but Hywel invaded and drove them from the kingdom.