Site: Offa’s Dyke, Gloucestershire
What it represents: The origins of British society in warring Anglo-Saxon kingdoms in the aftermath of Roman rule
The plinth stone: A piece of stone from the rampart of the dyke
Provenance: Collected in 2007 from an area of erosion on the dyke just north of Devil’s Pulpit
Maximum dimension: 134mm
Loaned by: Archaeology Service, Gloucestershire county council
Offa’s Dyke is the longest earthwork in the British Isles, a bank and a parallel ditch to its west – the Welsh side – that wind their way back and forth across the modern border between Wales and England. Some 110km (70 miles) of the dyke’s route is followed by the Offa’s Dyke national trail, which runs from the Severn estuary near Chepstow in the south to the Welsh coast at Prestatyn in the north. Near the limestone crag known as the Devil’s Pulpit, not far from Chepstow, the bank is being eroded by walkers attracted by the trail and the spectacular views of the river Wye and Tintern Abbey 200m below.
Within a landscape heritage scheme managed by Wye Valley AONB (called Overlooking the Wye), Gloucestershire county council Archaeology Service and the Forestry Commission, advised by English Heritage, are proposing works in this area to consolidate the path and protect the monument from further erosion. The plinth stone was collected as a guide for colour and texture for any stones that might need to be imported for restoration work.
Offa’s Dyke entered history around AD893, when Bishop Asser described it in his Life of King Alfred: “a great bank between Wales and Mercia” was, he said, built by the “fearful king Offa… from sea to sea”. Offa was ruler of the Anglo-Saxon kingdom of Mercia from 757–796. Archaeologists and historians disagree over details of the dyke’s route, and how long it really was (there are substantial gaps in Herefordshire in particular) – and also over the extent to which it was designed to physically defend Mercia, or instead to make a statement of power.
What is undisputed is that Offa, who may occasionally have styled himself “king of the English”, extended his authority through force and alliance across much of the territory once governed by Rome. For us today Offa’s Dyke represents the achievements of a shadowy ruler who was regarded as an equal by Charlemagne (whose empire encompassed much of western and central Europe). He may have been driven more by ambition than ideals, but his reign typified the era in which petty kings and chiefs vied for power in the centuries after Roman withdrawal, and when some of the key elements of modern Britain were being laid down.
Where the plinth stone was collected, the dyke (a scheduled monument) lies on the English side of the Wye valley, achieving its visual impact by its siting rather than its size – though up to 7.5m high elsewhere, here the bank may have risen no more than 2m. There is a line of pits at the back from which the bank was quarried.
Cyril Fox, 1955. Offa’s Dyke: a Field Survey of the Western Frontier Works of Mercia in the Seventh & Eighth Centuries AD. Oxford University Press
David Hill & Margaret Worthington, 2009. Offa’s Dyke: History & Guide. History Press
Ernie Kay, Kathy Kay & Mark Richards, 2007. Offa’s Dyke Path South (National Trail Guides). Aurum Press
Ernie Kay, Kathy Kay & Mark Richards, 2008. Offa’s Dyke Path North (National Trail Guides). Aurum Press
Frank Noble & Margaret Gelling (ed), 1983. Offa’s Dyke Reviewed. British Archaeological Reports