Gruffydd ab Owain

Gruffydd ab Owain (died ) was a joint king of Glywysing in Wales along with his brother Cadwgan in the early tenth century. His other brother Morgan ruled in Gwent. He was a grandson of Hywel ap Rhys (Glywysing), who united and ruled the Kingdom of Glywysing in south east Wales at the end of the 9th century. The second brother Cadwgan ab Owain died c. 949 0r 951, "murdered by the Saxons" and ruled as joint kings of Glywysing with Gryffyd. Phillimore's reconstruction of the dates places the entry in AD. 935. Afterwards, his brother Cadwgan seems to have ruled Glywysing alone until his death .

Following his brothers' deaths, Morgan absorbed their kingdom into his and united the former kingdoms of Gwent and Glywysing in 942 under the name of Morgannwg. Morgan paid homage to the English kings as a form of protection and is recorded as witnessing royal charters for Kings Æthelstan, Eadred and Eadwig.