OFFA’S Dyke – known in Welsh as Clawdd Offa – is a defensive structure named after the 8th century Anglo-Saxon king of the ancient English kingdom of Mercia, although it is commonly believed to have been built before his time.
Offa ruled his fiefdom with an iron first from AD757 until AD796, and without doubt utilised and strengthened the Dyke to protect his land from interlopers from various Welsh kingdoms to the west, Powys in particular.
However research work, including carbon dating, seems to suggest that the construction of what is today known as Offa’s Dyke commenced in the early 5th century, soon after the departure of the Romans.
It was the largest building project in Europe in its time, built it is believed by means of a corvée system by which commoners worked un-paid for their rulers as a form of tax. It was first ascribed to Offa by the Welsh monk Asser, biographer to Alfred, the 9th century king of Wessex. He wrote in AD893: “There was in Mercia in fairly recent times a certain vigorous king called Offa, who terrified all the neighbouring kings and provinces around him, and who had a great Dyke built between Wales and Mercia from sea to sea.”
Much of it does indeed follow the present-day boundary between Wales and England, even if it was never a complete defensive structure from coast to coast. In particular it seems that it was never extended to reach the northern coast. However there are suggestions that the less well known Wat’s Dyke, built even earlier and stretching southwards from the Dee estuary, was somehow integrated into the whole defensive structure.
The Dyke remained an important political and geographical marker way after Offa’s time. The Patent Rolls, the administrative records of the English crown, still referred in 1223 to the folk of Chirbury in Shropshire as being “this side of Offediche”. To this day some people in Wales will refer to their English neighbours as being “from the other side of the Dyke”.
It is undoubtedly a remarkable earthwork structure, up to 20m wide and 2.4m high, and evidence of the digging and quarrying for the construction materials used can still be seen here and there along its length. It features a bank on the eastern side and a deep ditch on the western side, a seemingly perfect defensive combination that was however regularly breached.
Much of it is still perfectly visible, and it is in remarkably good condition in many sections, particularly so an unbroken linear section running between Knighton in Powys and Llanfynydd near Wrexham. Offa’s Dyke Centre in Knighton offers a fascinating insight into the Dyke’s history.
Offa’s Dyke Path is a long distance trail of some 285km from Prestatyn in the north to Chepstow in the south, or vice versa, that closely shadows the Dyke’s route in many parts, particularly so in its central sections. It was inaugurated in 1971.