The Enigma of History

Offa's Dyke and the Clun Valley

You know how it is, a question pops into your head, and you've just got to find the answer. No matter how obscure the issue, or how irrelevant it is to everyday life, you've just got to know.

This happened to me a few days ago when I was studying a map of the area in which I was brought up. I was pin pointing where my relatives lived, and it was as I was looking at Ruabon that the question popped into my mind.

On the west side of the village was a line marked Offa's Dyke, and on the east side, under a mile away, was a line marked Wat's Dyke. The question that wouldn't go away was why were there two earthen Dyke's running so close to each other? And a subsidiary question was, while we'd all heard of Offa's Dyke, why hadn't I heard of Wat's Dyke? It was barely two miles from where I was born. This niggled away at me, and I had to look into it.



Offa's Dyke is Red Line and Wat's Dyke is Brown Line

 I've dipped into about half a dozen archaeological works to find the answer, and there is conflicting views, particularly about Wat's Dyke.

However, digging through the mystery and the speculation, and the view that "nearly everything about Wat's Dyke remains uncertain", I'm hanging on to a consensus view, that makes sense to me. If my reader knows something else, they will no doubt let me know.

Wat's Dyke is up to 60 miles long, running from Basingwerk, Holywell, Flintshire, down to the river Severn at Maesbury in Shropshire. You can read about the Wat's Dyke Way Heritage Trail here.

Offa's Dyke is much longer, and runs from Prestatyn in the north, to Chepstow in the south,  a distance approaching 180 miles. The Dyke roughly follows the existing border between England and Wales. You can see the Offa's Dyke Association web site here.

I still hadn't answered my question of why, but I became captivated by the thought of what. What did the Dyke's look like? And reading about them took me back over 50 years to school drawings of castle escarpments (I hope that's the right word).

The Dyke's were generally, for most of their length made of a ditch, the soil of which was then made to construct a rampart. A bit like planting a row of potatoes, but a lot, lot, lot bigger. The Wat's Dyke varied in size over its length, with the rampart reaching anything from 6.4m to 12.2m in height. At Wrexham General Station, the bank was found to be over 6m wide, and the ditch in many places was at least 1.2m deep. Offa's Dyke was much bigger altogether, and as originally constructed, it was thought to have been about 27m wide, and 8m from the ditch bottom to the bank top. As can be seen from the diagram above, the ditch was always to the west, facing Wales.

The British Isles about 802 AD

So, who built the two Dyke's, when and why? At last I'm coming to answer my question, at least in a way that satisfies me.

The general consensus seems to be that Wat's Dyke was built by Aethelbald, king of Mercia from 716 - 757 AD. Mercia at the time was largely the area that we now call the English Midlands. The name Wat seems to be of uncertain origin.

King Offa was Aethelbald's successor, and reigned from 757 - 796 AD, and was responsible for building Offa's Dyke, which was an improved version, being much stronger and longer. It is thought to have been started in 785 AD and taken many years to build. To understand how and why such an impressive Dyke came to be built, it's perhaps helpful to look briefly at Offa himself.

One historian has summarised him like this. "Offa was King of Mercia from 757 to 796 AD. His kingdom covered the area between the Trent/Mersey rivers in the north to the Thames Valley in the south, and from the Welsh border in the west to the Fens in the east. At the height of his power, however, he also controlled Kent, East Anglia and Lincoln, and had alliances with Northumbria and Wessex, sealed by the marriage of two of his daughters to their Kings, Aethelred and Beorhtic respectively. He was, therefore, effectively an early King of England".

In response to the unrest emanating from the Princes of Powys along the Welsh border, he constructed the Dyke; either as an agreed boundary, defensive structure, or some other reason; historians and archaeologists are uncertain. Speaking as a layman, I think that there would have been easier ways to mark a boundary, and I can only assume that it was built to help keep the Welsh out of his kingdom of Mercia. The ditch facing Wales leads me to this view. He built it west of Wat's Dyke, so extending his own kingdom further into Wales.

It's amazing that after over 1200 years, so much of the Dyke's remain. I think that's testimony to the worker's of the day, and hundreds and thousands of walkers every year are enjoying the fruits of their labour. To another historian, "the origins of the Dyke are shrouded in mystery so that many of its aspects are speculated upon rather than being fully understood". What I've written may well contain some speculation, but I'm content that my questions of why, who and what have been answered. I now await the next question to pop into my head.