Llys Arthur or `Arthur's Court? first appears with that name on Lewis Morris's 1748 map of the Mannor of Perverth and is mentioned by George Borrow in his tour of `Wild Wales?. Lewis Morris's map shows the site lying south-east of `Lluest Troed rhiw widdon?, a deserted farm (which survives as earthworks of a long house at SN 7863 8266) at the foot of Foel Wyddon. Llys Arthur lies just under a kilometre north-east of Fagwyr-fawr farm, this placename denoting a `great ruin? potentially of Roman origin. Taken together, the place names may denote human occupation or even metal exploitation here in later prehistory or Roman times. The similarly-named metal mine at Ogof Wyddon (Witch's cave or Wizard's cave; NPRN 34008) near Machynlleth was shown, through excavation by the Early Mines Research Group, to have origins in the Bronze Age. At its time of historic re-opening as a mine in 1856, the site had apparently gone out of knowledge as a mine but was haunted by legends of `ghosts, hobgoblins and fairies?. Simon Timberlake considers this to be a potential folk memory of the prehistoric metallurgy which took place here.

The Llys Arthur earthwork lies towards the head of the Afon Castell valley at an altitude of 280m O.D., in an open tract of fairly level pasture. Surface topography and information from aerial photographs shows a considerable number of former stream channels across this upland tract prior to extensive drainage, and this must always have been a wet location.

The site is a rectangular embanked enclosure with rounded corners, about 55m north-east to south-west by 36m internally. It is set on almost level ground falling very gently to the south-east. On the south-west side the enclosure rests against & below a low, but pronounced scarp line. There is a central gap in the north-west side. There is no trace of a ditch except on the south-east side. Here there is a broad ditch c,5m wide with a broad counterscarp bank. The enclosure is presently incomplete on the east side, with seemingly no surface trace of any former or vestigial earthwork. However, Royal Commission aerial photographs taken under drought conditions on 27th July 2006 reveal sub-surface washes of gravel from previous flooding events of the Nant Coch Mawr. This parched detail clearly shows flood events washing gravel along the line of a now vanished earthwork and even marking the site of a now vanished central entrance gap in this side. Only geophysical survey would now reveal the position of this former earthwork.

There are indications of a north-west to south-east range, at least 20m by 10m in the western part of the interior but these building footings appear to be intrusive, cutting into the former line of the earthwork. Some 35m due west of the enclosure is a pronounced low mound which may be artificial in origin.

In late February and early March 2013, Keith Haylock, a doctoral student at Aberystwyth University's Institute for Geography and Earth Sciences, supervised by Toby Driver (RCAHMW), under took a 5m gridded sampling of the enclosure (with Scheduled Monument Consent) with a hand-held pXRF scanner to sample for concentrations of metals in the subsoil. Provisional results show a concentration of lead and other metals within the enclosure, compared to low background levels beyond, very likely originating from anthropogenic activities.

The date of this interesting earthwork remains problematic. As a medieval moated site it would be highly unusual in a regional context, although it may be a rare survival of a medieval hospitium, or even a true Early Medieval Llys or court. Its strategic position at the head of a valley, west of Cae Gaer Roman fort at the head of the Wye, suggests a Roman military origin. However, while the morphology of the earthwork, with its rounded corners, is of Roman appearance, the broad, squat nature of the earthwork together with the broad southern ditch is more unusual. A workable hypothesis would be that the site began life as a Roman military site and was subsequently developed in the Early Medieval and Medieval periods, too useful and well positioned as a structure to be ignored by subsequent generations.


T. Driver, RCAHMW, 2013