Idwal inherited the throne of Gwynedd on the death of his father
Anarawd ap Rhodri in 916. His paternal grandparents were
Rhodri Mawr, King of Gwynedd and
Angharad ferch Meurig of Ceredigion. Idwal allied himself with King
Æthelstan of England upon the latter's accession in 924. As Æthelstan was eager to establish his authority across Britain, Idwal honoured him by visiting the
English court in 927, 928 and 937. On the first of these visits, he signed charters agreeing to campaign with Æthelstan against the
Scots, and marched with
Hywel Dda of
Deheubarth and
Morgan ab Owain of
Gwent against
Owain ap Dyfnwal, King of Strathclyde that year. Owain was forced to submit to the English king and appear at court by Christmas. Æthelstan died in 939 and was succeeded by his half-brother
Edmund. In 942 Idwal, apparently fearing that the Saxons would support Hywel in usurping him, launched an attack on the Saxons in Wales along with his brother
Elisedd. 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 Dda invaded and drove them from the kingdom. He reigned for eight years before the brothers were able to return and reclaim their patrimony following his death in 950. == Children ==