Owain had soon returned to Powys from Ireland and made an alliance with Madog ap Rhiryd.

The king had responded by releasing Owain's uncle, Iorwerth ap Bleddyn, from captivity in 1110 and returning the rule of Powys to him.

Owain had been driven out of Powys by Iorwerth and retreated to Ceredigion, whence he made raids on Dyfed, selling his captives in the Irish slave markets.

He also killed a prominent member of the Flemish colony, William of Brabant.

King Henry had responded by stripping Cadwgan of all his lands and forcing him to live as an exile in England, while Owain again fled to Ireland.

However Iorwerth had been killed by Owain's ally Madog ap Rhiryd in 1111 and the rule of Powys was returned to Cadwgan, who was allowed to recall Owain.

When Cadwgan was also killed by Madog the same year, Owain had become ruler of much of Powys.

He employs his uncle Maredudd ap Bleddyn as penteulu (captain of the guard), and in 1113 Maredudd is able to capture Madog ap Rhiryd and send him to Owain.

Owain takes vengeance for the killing of his father by blinding Madog.