The landscape context of Offa’s Dyke is a story from prehistory to the present day. I recently visited a key point on the line of the late 8th-century AD monument north of Chirk which reveals an important dimension of this complex and multi-phased landscape history linking the early medieval frontier work to the industrial age.
The Mercian dyke cuts across the lie of the land in this key strategic area, blocking movement west and east along the Ceiriog and Dee rivers as they spill out of the Welsh uplands into the Cheshire plain. For the Ceiriog valley, it heads down the banks of each valley in a curve to allow it to overlook the valley. For the Dee, on the south-side of the Vale of Llangollen, north of Chirk, it drops down towards the River Dee at Ty Mawr where it hits the river at a striking river-cliff. The Dyke then uses the southern bank of the river as its line for c. 1km around a bend before rising northwards at a different location and heading uphill towards modern-day Ruabon.
On the south side of the Llangollen vale, in the first years of the 19th century, the Llangollen Canal was cut from Chirk to Froncysyllte perpendicular to the line of the Dyke: the canal follows the contour, while the earlier Dyke was running across the contours.
This affords an important point to today reflect on the relationship between two contrasting engineering projects separated in term by over a millennium. The canal cutting affords a prominent place to view the Dyke’s bank and ditch upslope and appreciate its scale in even a denuded state. It also allows one to view northwards and see the line of the Dyke heading downslope towards the Dee.
There is a further reason why this point is significant: this is the farthest north that the Offa’s Dyke Path National Trail – here following the towpath – intersects with the monument. From here north to Prestatyn, its route bears no relationship with the Dyke.
While the significance of this Path/Dyke intersection isn’t recognised, the ‘meeting of marvels’ is commemorated by an interpretation post beside the towpath. The post has three plaques. Two comprise a single bilingual message – the Welsh one facing east, the English one facing west, explaining the Dyke.
The image is one adapted for use elsewhere up and down Offa’s Dyke, and it attempts to shows Offa haughtily overseeing the digging of the earthwork. Usefully, but somewhat misleadingly, the Dyke is shown here descending towards a river and ascending on the opposite bank. This is misleading (as noted above) because this doesn’t happen with the Dee, where the Dyke jumps a mile-or-so eastwards and ascends from the Dee at a different point (Hopyard Wood).
Meanwhile, the text outlines how the Dyke might have served many functions, posing the question: ‘What do you think?’ The third side has a map of the Path and the Dyke associated with it.
What is perhaps frustrating is that, while people might stop and look at the post, they might not really be able to discern where they are supposed to apprehend the Dyke itself. Perhaps a marker on the other side of the canal would help? Perhaps some tree clearance up and down slope would help too?