Thomas Frederick Tout , Dictionary of National Biography… (1895)
“ In 1171 Rhys again invaded Powys, and forced Owain to surrender seven hostages for his good behaviour. But a quieter time now followed in Wales. Davydd, prince of Gwynedd [see Davydd I] , Owain Gwynedd's son and successor, was Henry II's son-in-law. The Lord Rhys had become the king's 'justice in South Wales.' Henry found it wisest to leave the Welsh princes pretty much to themselves, and they on their part found it prudent to recognise his supremacy. Power in Wales was, moreover, so divided that no single Welsh prince had much chance of winning great triumphs over his neighbours. ”
