Hyfaidd's sons Llywarch and Rhodri reigned after him, but the kingdom was soon lost to Cadell's son Hywel who consolidated his realms as Deheubarth.
Castle Nimble (also called Knapp; Maes Hyfaidd; Maes Hyvaidd) was a motte and bailey defensive fortification near Old Radnor, in Radnorshire (modern-day Powys), Wales.