§ 1. a.d. 948. Howel Dda left behind him four sons: Owen, Rhun, Rhodri, and Edwyn, whose several and collective claims to his dominions were instantly and furiously contested by the five younger sons of Idwal Foel. After several conflicts, it was agreed that the sons of Howel Dda should divide South Wales and Powys between them, and that Iefan and Iago, the second and third sons of Idwal Foel, should reign jointly over Gwynedd, Meurig, the eldest, being set aside as unworthy; but this arrangement formed merely a basis for contention, because the supreme sovereignty was assumed by Iefan and Iago, and their right to it was denied by the sons of Howel Dda.

The military strength of Gwynedd was summoned by Iago and Iefan to decide the question, and the combined forces of Powys and Deheubarth, led by Owen ab Howel and his brethren, quailed before it, and were vanquished with great slaughter upon the hills of Carno in Montgomeryshire. In the following year, the victors twice ravaged Dyfed, and, in one of these expeditions, they slew its local king. About the same time died Rhodri, one of the turbulent sons of the peaceful Howel Dda.

About the year 954, the surviving sons of Howel Dda having resolved to assert their ascendancy, and to retaliate the ills which had been inflicted upon their provinces, collected the military strength of Deheubarth and Powys, and marching into Gwynedd, ravaged the country as far as the river Conwy.