Morgan ap Morgan ab Owain

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Iorwerth ab Owain (d. 1175x84), prince in Wales, lord of Caerleon, succeeded the king, his elder brother Morgan ab Owain, on Morgan's violent death in 1158. There is no indication that Iorwerth ever used the royal style, derived from their grandfather, Caradog ap Gruffudd (d. 1081), one-time dominant king of Gwlad Morgan and client of William I. Iorwerth's first appearance is in 1136 when Gerald of Wales names him as the man responsible for the killing of Richard de Clare of Ceredigion in the pass of Grwyne Fawr between Abergavenny and Talgarth. In the subsequent conquest of Upper Gwent and Llefennydd by Morgan ab Owain, Iorwerth was closely associated with his brother. They issued joint charters in Stephen's reign, and even appear to have possessed a joint seal (although no impression of it survives). Although King Morgan left at least two sons, it was his brother who succeeded him in 1158. This was quite clearly because Iorwerth had occupied the position of heir designate (edling) during his brother's lifetime.

Iorwerth's nephew, Morgan ap Morgan ab Owain, seems always to have supported the English rather than his uncle. Caerleon Castle was once more lost.