Ewias

Ewyas (Welsh: Ewias) was a possible early Welsh kingdom which may have been formed around the time of the Roman withdrawal from Britain in the 5th century. The name was later used for a much smaller commote or administrative sub-division, which covered the area of the modern Vale of Ewyas (now within Monmouthshire, Wales) and a larger area to the east including the villages of Ewyas Harold and Ewyas Lacy (now within Herefordshire, England).

Some researchers interpret the evidence of the medieval Llandaff charters to suggest that early Ewyas may have encompassed much of south-east Wales, including the later kingdoms of Gwent and Ergyng. However, these sources are open to several interpretations and this is not generally accepted by mainstream historians. Geoffrey of Monmouth gives the legend of Octavius (Welsh: Eudaf), "earl of Ewyas and Ergyng", in his famous pseudo-history Historia Regum Britanniae, making him a descendant of Caratacus who had led the Silures in battle against the Romans. According to Geoffrey, he took up a supposed "British High Kingship" after defeating Trahern, the brother of King Coel Godhebog, in the late third or early fourth century. There is no historical evidence to corroborate this and Coel's reign in the Hen Ogledd is usually placed in the 5th century. In the Welsh versions of the Historia, such as Brut Dingestow, Octavius is called Eudaf; this is the same legendary figure that appears in Breuddwyd Macsen Wledig as father of Elen, wife of Macsen Wledig, and living near Segontium in north Wales.

...
Wikipedia