Owain ap Dafydd (c. 1265 – c. 1325), de jure Prince of Gwynedd (1287-c. 1325), was the younger son of Dafydd ap Gruffydd the last free ruler of Gwynedd and self-proclaimed Prince of Wales. Nothing is known of his early life, though it is thought likely he accompanied his father during periods of exile in England in the 1270s.

Following the death of his uncle Llywelyn the Last in late 1282 the governance of Gwynedd was assumed by his father Dafydd ap Gruffudd. He and his father were captured together, after a struggle, close to Cadair Idris on 21 or 22 June 1283. Shortly after this Dafydd was brought to Shrewsbury where he would be executed for treason in October.

Following the arrest of his elder brother Llywelyn on 29 June they were both escorted under guard out of Gwynedd via Acton Burnell to Bristol Castle. Llywelyn would die in 1287 while Owain was last reported to be alive in 1325 when he would have been in his sixties. During much of his captivity at Bristol - and we must assume the same treatment, or worse, for his brother - he was kept in a cage to ensure there was no means of escape. Order from King Edward I to the Constable of Bristol Castle, October 1305:

As the King wills that Owain son of Dafydd ap Gruffudd, who is in the Constable’s custody in the castle, should be kept more securely than he has been previously, he orders the Constable to cause a strong house within the castle to be repaired as soon as possible, and to make a wooden cage bound with iron in that house in which Owain might be enclosed at night.

The exact date and circumstances of his death are not known. After his death the de jure Prince of Gwynedd would have been his cousin Thomas ap Rhodri.

References

Llewelyn ap Gruffudd, Prince of Wales (J. Beverley-Hughes, 1998)