1. Caer Drewyn is a great stone-walled Iron Age hillfort, set on sloping ground below the summit of a long ridge extending west into the lowlands of the Dee Valley, north of Corwen. The site is first mentioned in c.1600 where its construction is attributed to a hero or giant Drewyn Gawr (RCAHMW 1921, 13).
The hillfort has three main phases of construction, the earliest thought to have been a smaller curvilinear earthwork fort at the highest point on the north-east side of the later hillfort. This partly survives as an earthwork outside and to the east of Caer Drewyn. The main stone-walled hillfort is built from scree rubble, and cuts across this earlier fort extending downslope and enclosing 3.36 hectares. Numerous traces of stone facing suggest that the rampart originally took for the form of a high stone wall, perhaps with an inner wall-walk. The fort measures overall c. 192m north-south by 215m east-west, and features fine in-turned stone-built gateways to the west, at the foot of the slope, and to the north-east at the highest point. Aerial photographs taken in winter light show traces of hut platforms or scoops in the central and eastern part. At a later date, a triangular annex was added externally to the north-east of the fort, in-part reusing the earlier earthwork of the first fort. One or two foundations of round houses are visible within this annex and it may be that this dates to Romano-British times, concievably when the main hillfort had ceased to function as a settlement. The site was investigated in the later nineteenth and earlier twentieth century, when sections of the ramparts were cleared of 'clatter'. There were no datable finds. It is generally believed that Owain Glyndwr made use of Caer Drewyn as an occasional retreat (Pennant). A new survey was completed by Engineering Archaeological Services Ltd for the Heather and Hillforts Landscape Partnership Scheme (Denbighshire County Council) in 2007.
The environs of the fort are noteworthy in preserving traces of an extensive field system to the north-east of the fort (NPRN 309746). It is impossible to date these fields but it is very likely they have prehistoric origins. Some 700m to the north-east, beyond the field systems, is a well-preserved Iron Age concentric enclosure set low down on the north-west facing hillslope (NPRN 54431).
Sources: Prichard in Archaeologia Cambrensis 5th series 4 (1887), 241-52
RCAHMW Inventory VI, County of Merioneth, 1921, 13-16.
Gardner in Archaeologia Cambrensis 77 (1922), 108-125
Savory in Archaeologia Cambrensis 107 (1958), 135-6
Toby Driver, RCAHMW, 17 June 2008.
2. Full tour entry from Driver, T. 2023. The Hillforts of Iron Age Wales. Logaston Press. 258-261.
A great stone-walled hillfort of the north: Caer Drewyn, Corwen.
Caer Drewyn is one of the most interesting hillforts of northeast Wales, being built largely of scree with good sections of Iron Age rampart walling still visible. The hillfort gained its name from the hero or giant Drewyn Gawr to whom its construction was attributed when first mentioned around 1600, at which time it was noted as being occupied as a ‘hafod’ or summer farm in the middle ages. In the seventeenth century antiquarian Edward Lhwyd noted Caer Drewyn as the ‘place where they kept their cattle in war time’.
Caer Drewyn is strongly positioned high up on the leading western slope of the Llantysilio Mountain uplands, a block of high ground extending west to visually command a wide lowland valley junction above the Vale of Edeirion. The hillfort occupies a detached ‘island spur’ of the mountain, as the tiny river of the Morwynion cuts a valley northwards separating Caer Drewyn from higher ground to the east. The great lowland plain below the hillfort was a meeting point for routeways through the hills in prehistory. A Roman marching camp was built just above this valley junction at Penrhos, Druid, 4.5 kms west of Caer Drewyn, further attesting to the strategic importance of this wide lowland vale during their campaigns. Caer Drewyn hillfort even occupies a ‘tipped’ or sloping position to look down into, and thus visually command, the valley below.
Hillforts built of scree are rare in northeast Wales but here the abundant building stone was fully utilised. Much of the lower half of Caer Drewyn’s rampart is a broad earthwork rampart with a tumbled outer facing of scree, while the upslope half of the hillfort is almost entirely built of scree. The ramparts form a great oval enclosure with no obvious traces of a ditch. The fort measures 192m north-south by 215m east west and encloses 3.36 hectares. It sits on a steep hillslope facing west, with opposing gateways at the top and bottom of the slope separated by 40 metres of ascent; the ruinous main gateway sits on the level ground of the hill summit. There are around thirteen house platforms within the hillfort, identified during survey for the Heather and Hillforts Programme. It may be that many more ephemeral buildings and structures once stood here but a geophysical survey did not reveal much more detail. Gardner also notes a water source in the form of a spring below the western gateway.
The hillfort was first explored by an antiquarian archaeologist, the Reverend Hugh Pritchard, who cleared away the ‘clatter’ from parts of the rampart, publishing his results in 1887. Subsequent clearance and survey by Willoughby Gardner early in the 1920s noted the rampart consisted of ‘..a core of rubble stones, faced either side with a wall of dry masonry’. The wall was better built on the outer face, presumably for purposes of display. Gardner found evidence for a stepped profile with an upper platform or wall-walk 1.5 metres wide, an advanced feature also found at Tre’r Ceiri on Llŷn. He proposed the original wall may have stood between 4.2 and 4.6 metres high. There are many oval shelters within the rubble of the rampart built by farmers, walkers and soldiers on manoeuvres in recent centuries to provide shelter in inclement weather; they were first mentioned by Pennant in the eighteenth century.
The main gateway at the northeast point forms an inturned passageway between the terminals, a type of gate which was common among the hillforts of northeast Wales including at Pen y Corddyn and Dinorben. It would have formed an intimidating entrance to this hillfort. In contrast to the visible wall sections around the rampart, the gateway itself is ruinous today and partly infilled with rubble. The siting of the main gate on the level ground of the hill summit may suggest that most visitors and traffic were expected from this direction; in 1922 Willoughby Gardner also noted ‘numerous points of rock sticking up across the causeway’ which he took to be a natural chevaux-de-frise.
Immediately outside the main gateway on the hill summit is what appears to be a later defended hut group, appended onto the earlier rampart. It may be that the hillfort was entirely defunct when this enclosure was built, or perhaps simply reserved for the penning of livestock. On the hillslopes beyond lie quite extensive remains of prehistoric fields and settlements.
The key to Caer Drewyn’s siting and construction probably involved several factors. The availability of scree on the hillslopes provided a novel building material for the Iron Age community. The choice to ‘tilt’ the hillfort to the west down a 40m slope, may have been influenced partly by the scatter of scree down the slope, but was probably also a strategic decision to allow visibility over the valley below. Perhaps a final critical factor is found outside the eastern ramparts on the hill summit. Just outside the fort is a great wet bog, lying in a gully between the fort on the west and the rocky local summit of the hill above to the east, mentioned by Gardner as a former ‘shallow tarn’. This bog must have been a useful source of water and fuel, but was it more than that? Given the importance of wetlands and bogs for religion and ceremony in Iron Age Wales, the fort may well have stood on the edge of a sacred wetland, a ‘portal to the underworld’ set only a few metres beyond the gateway to the hillfort and perhaps a key ceremonial focus that underpinned at least some of the function of Caer Drewyn.
Updated: Toby Driver, RCAHMW, March 2024