A chance discovery of an ancient Celtic shield in a field in Leicestershire is helping to transform the academic world’s understanding of prehistoric warfare.
It suggests that ancient European warriors were able to fight in an even more fluid and fast-moving fashion than previously thought.
Until now, the evidence found by archaeologists around Europe has suggested that the heaviest piece of equipment used by ancient warriors – their shields – were mostly made of metal or solid timber.
But the new Midlands discovery, described by the British Museum as being of international importance, reveals that, instead, some of their shields were designed in a particularly sophisticated way to ensure that they were extremely light.
Probably because they have tended to survive better, dozens of metal shields have been found throughout Britain and continental Europe. Typically they weigh in at around three kilos.
A few wooden examples have also been found – and they would originally have weighed around two kilos.
But the newly-analysed ultra-lightweight 2400-year-old Leicestershire shield – the first of its kind ever found anywhere in Europe – is made not from metal or ordinary timber, but from bark and may have weighed as little as 0.6 kilos.
The discovery reveals that the ancient Britons used the same lightweight shield-making material used at least in more recent centuries by Aboriginal Australian warriors.
It is likely that the Leicestershire shield was actually used in at least one battle. It has two probable spear impact marks and two probable blade marks, potentially made by metal swords.
Each blade impact mark gives a fascinating clue as to the defensive properties of bark shields.
Bark is more resilient than metal or wood – so sword blows (and arrows) tend to fully or partially rebound off them.
In the case of the blows which caused the blade impact marks on the Leicestershire shield, the blade had quite literally bounced off and back onto the surface, thus producing parallel five centimetre long repeat impact marks, just a few millimetres apart.
It demonstrates the almost rubber-like deflective nature of the shield’s bark composition.
But to make the bark behave in that extremely effective way, the shield’s Iron Age makers had to employ some very sophisticated manufacturing techniques, researchers have discovered.
First, they had dried the bark in such a way as to give it an inbuilt rubber-like weapon-deflecting “bounce” capacity.
They achieved this by inducing tension in the bark, as it dried, by deliberately bending it in the opposite direction to its natural tree-surface curve.
This enabled the inner face of the bark to become the outer impact-absorbing “business” face of the shield.
It is this deliberate curve-reversal-induced tension which gave the shield its protective qualities – and it was the ultra-lightweight nature of bark (as opposed to metal or ordinary timber) which would almost certainly have allowed the warriors to fight more agilely and for longer.
The archaeologists found the shield in what in prehistoric times had been a two-metre deep water-filled 3.5 by two-metre man-made pool, apparently located some way from the nearest settlement.
It’s not known for sure what the purpose of the pool was. However, it was deliberately re-dug and reused several hundred years later – so it is conceivable that the artificial pool or at least its location had an importance that survived across many centuries.
Perhaps significantly, the pool had had its own metalled Iron Age trackway leading to it. The site is also located very near to the Fosse Way – a Roman road, which some scholars believe may have had Iron Age origins.
The archaeologists have not yet definitively concluded why the shield was placed in the artificial pool – but prehistoric reverence for watery places might suggest that the shield was deposited there as a votive gift to the gods – potentially after a successful battle.
Only one other potentially significant artefact was found in the pool – a 77 centimetre long, six centimetre wide and 1.8 centimetre thick length of trimmed split oak which may originally have been a staff, cattle goad or other artefact.
The shield, which originally measured at least 67 x 37 centimetres, was found 4.8 km (3 miles) southwest of Leicester, as part of routine investigations on the site by University of Leicester Archaeological Services archaeologists on behalf of local brewers, Everards of Leicestershire.
The detailed scientific analysis and investigation of the shield, originally unearthed in 2015, has taken more than three years to complete.
It had been carefully constructed with a wooden rim, five very thin wooden laths to stiffen the structure and a beautiful woven basketwork-style willow and grass (or tree bast) boss to protect its wooden handle.
The outside of the shield had been scored and then painted in red chequerboard decoration. Radiocarbon dating has revealed that it was made between 395 and 255 BC.
The bark – from which most of the shield is made – probably came from willow or alder trees.
The project has been led by Matthew Beamish of University of Leicester Archaeological Services, with the analysis of the shield itself managed by Mike Bamforth of the University of York.
Many cutting-edge analytical techniques have been used to understand the construction of the object, including Reflectance Transformation Imaging (to identify and analyse weapon impact marks), molecule identification spectroscopy (to determine the chemical makeup of the paint) and CT scanning and 3D printing at Leicester Royal Infirmary.
Combat experiments with replicas of the shield have taken place over the past year.
On the discovery, Matthew Beamish said: “We have learned a great deal from fragile evidence which could have been so easily overlooked, and the project has been a wonderful collaboration providing a rarely seen glimpse of our prehistoric past.”
The University of York’s Mike Bamforth said: “This truly astonishing and unparalleled artefact has given us an insight into prehistoric technology that we could never have guessed at.”
Dr Julia Farley, curator of British and European Iron Age Collections at the British Museum, said: “This is an absolutely phenomenal object, one of the most marvellous, internationally important finds that I’ve encountered in my career.
“So often it is gold which grabs the headlines, but this bark shield is much rarer.”
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