History has bequeathed us many fascinating and intriguing monuments and here, in Wales, we are well endowed with such relics. None of them, however, is more striking than the magnificent remains of Offa's Dyke.
The Encyclopedia of Wales makes what is surely the definitive statement about the dyke and its purpose when it comments that: "The separateness of Wales is signified in the border landscape by the presence of this monumental earthwork, the biggest engineering project in Europe at the time of its construction in the eighth century."
Offa's Dyke is a huge ditch, in places over 60 feet in width, backed by a high earth bank, that runs for almost the full length of Wales. It follows, largely, the Welsh-English border and was built in the eighth century by Offa, king of the powerful Saxon province of Mercia that butted onto the eastern flank of Powys.
The dyke was a frontier line between Mercia and the smaller Welsh kingdoms to the west, in particular Powys and was, in its own way, as significant as Hadrian's Wall in the north of England.
Offa, an immensely powerful chieftain, was king of Mercia between 757 and 796 AD. The very fact that he could raise or command a workforce of several thousand to dig and build the dyke gives testament to his strength, although the dyke was probably built by workmen from the various areas through which it passed rather than by one self-contained group of navvies.
The great European king and emperor Charlemagne officially recognised Offa's position and power – a significant tribute to a fellow king or leader in a time of considerable unrest.
The monk Asser, in his 10th century Life of Alfred, first attributed the dyke to King Offa, stating that he not only commanded and terrified all of the neighbouring chieftains and war leaders but that he "had a great dyke built between Wales and Mercia from sea to sea."
The reference to the earthwork running from "sea to sea" is a little misleading as there are missing sections of the dyke, particularly in the north and south, and the ditch probably never ran for the full length of the border.
The full distance from the Wye to the Dee is about 150 miles – Offa's Dyke probably stretched for about 60 or 70 of these.
An earlier earthwork, Wat's Dyke, runs almost alongside Offa's Dyke for some of its length, particularly in the Knighton area. The two ditches are rarely more than a few miles apart and, occasionally, come together in one united whole when the original engineers felt it was unnecessary to dig a new embankment.
The dyke runs straight as an arrow in some parts – a tribute to the technological skill of the men who excavated it – but then by-passes hills and other major landmarks, always cutting around the Welsh side of the obstacle. The aim, clearly, was give people on the Mercian or English side of the dyke a clear and open view into Wales.
With the displaced earth from the dyke piled high on the eastern side, its purpose was to denote or define the frontier rather than to defend it. The dyke would have regulated access to and from Wales while, at the same time, checking or halting border raids. It was also a hugely effective statement by King Offa, an example of power politics at its best.
The dyke may well have been patrolled by Offa's soldiers or even been provided with a system of early warning beacons but it was not garrisoned, like Hadrian's Wall, with detachments of troops. At this distance it is not always possible to tell. But, of course, the legends surrounding the dyke are many and varied and many of them make great stories.
George Borrow, the Welsh writer and historian, declared that for many years any Welshman discovered east of the dyke would have had his ears cut off – Englishmen found west of the earthwork were summarily hanged. There is little truth in the statement but it is all part of the legend of the dyke.
A long distance footpath, opened in 1971, follows much of the original route of the dyke, stretching from Beachley on the Severn to Prestatyn on the north Wales coast.
It is an atmospheric and often unfrequented area of the country, giving the walker a good impression of what it would have been like on Offa's Dyke in the eighth century. The Offa's Dyke Centre at Knighton is an informative place to start any exploration of the earthwork.
Longer than Hadrian's Wall and still, in many quarters regarded as the true border between Wales and England, Offa's Dyke remains a remarkably intact piece of our heritage.