Wat’s Dyke at Clwt, between Middle Sontley and Pentre-clawdd hill, Ruabon, is an important point of realignment of the Mercian frontier monument. The monument isn’t particularly impressive at this point, but the location deserves more attention that it has received to date.

To the north, this early ninth-century earthwork runs reasonably straight on a NNE-SSW course from the Rookery on the southern edge of Erddig Park past Middle Sontley, adopting a stance on the higher ground east of the NNE-flowing Black Brook all the way and taking in a series of modest crests in the landscape (a practice observed north of Old Oswestry hillfort). In contrast, to the south of this location, the earthwork adopts a markedly different, again straight, orientation, more NE-SW running to and from the prominent hilltop of Pentre-clawdd. The point of change of alignment at Clwt indicates a departure from the Black Brook to gain this higher ground before realigning again and heading on south through Wynnstay Park towards the Ceiriog valley.

Wat’s Dyke looking NW to the south of One Oak Cottage

Fox’s (1955) overall description of this section as ‘straight but sinuous’ is somewhat unsatisfactory, but he uses it to make the point that the ‘straightness of these alignments shows that the general course of the frontier between each natural obstacle was carefully thought out, prior to the consideration of the exact alignment to be followed from point to point’ (Fox 1955: 263). In his discussion, he regards this section as a point where two straight ‘minor alignment’ lengths shift (Fox 1955: 268).

In his survey, however, Fox has little to say but this:

Crossing the Black brook road, the cottage boundary fence is seen to be in the ditch of the Dyke. The banks seems to die into the rounded knoll; it certainly never was constructed on it, the contours being natural, the surface unaltered. The break here may well be due to two gangs having been at work who have not linked up, through bad staff work. The break is very short; 100 yards.

Wat’s Dyke looking south, just south of Clwt Cottages and One Oak Cottage

Given the repeated subsequent excavations of Wat’s Dyke by Margaret and David Hill and various other investigators that have repeatedly revealed extant banks and/or ditches at places where Wat’s Dyke has become denuded at the surface, including variegated survivals within Erddig Park, make it difficult to countenance Fox’s evaluation of an incomplete building and/or incompetence affecting this location. Moreover, it is interesting that the absence of Wat’s Dyke in this location coincides with a single field where it approaches the river, suggesting that livestock might have readily eroded the earthwork here where it isn’t preserved in a hedge line. In other words, the poor survival at this location most likely reflects vagaries of later medieval and post-medieval land use rather than an indication of an incomplete monument.

Looking south from the natural knoll, the bank of the monument appears again – the Black Brook is to the right

Beyond that point, I’d like to observe that the precise point of shifting alignment is very significant and precise: it lies where the Black Brook shifts its alignment at that very natural knoll described by Fox. Moreover, the dyke is able to go against the contour to the south, allowing water to flow along its ditch.

In other words, not only is this a distinctive, if subtle, promontory, it is a point where the water comes right up to the line of the earthwork and (to the south) along it. This raises a number of further possibilities. As at The Rookery where Wat’s Dyke veers westwards to take in a promontory overlooking the Black Brook, and at Pentre-clawdd to the south where the dyke skirts around the west side of a prominent hilltop rather than crossing it, I wonder whether ,at Clwt Cottages, did the earthwork here deviate from a straight line to encircle the knoll rather than run straight across it? Was this actually not only a point of realignment, and a point deployed in surveying the monument, but a strategic ‘fort’/watchtower/beacon location, perhaps even a gateway controlling movement along the Black Brook but also across it?

Water flowing along the line of what was the ditch of Wat’s Dyke, south of One Oak Cottage, looking SW.

My point can be seen clearly in this 1910s map, showing the position of Wat’s Dyke in relation to the shifting route of the Black Brook at a distinctive knoll.


While more work is needed at this location, I would suggest that the relatively low-lying and unpresuming nature of the Dyke at this point should not distract us from recognising this as a key strategic point in the line of the monument. Moreover, the ‘hydraulics’ of the monument are arguably an important part of its topographical emplacement.