The shield was discovered at Milsom’s Corner by archaeologists working on the South Cadbury Environs Project in June 1997. Some loose fragments of copper alloy had been recovered and indicated that the shield was made from thin sheet metal decorated with a rib and boss design.
Detail of the design on the shield
Funds for conservation were extremely limited, a bid was therefore submitted to the Heritage Lottery Fund. The initial challenge that the conservation team had to face was to produce an accurate estimate for conservation whilst the object was still encased in more than 75kg of wet soil.
Until funding was secured no work could commence and time was of the essence due to the fragile nature of the object. Visual and x-radiographic analysis of the shield indicated that complete mineralisation of the metal had occurred. In total, the shield was stored for a period of six and a half months until funding was secured from the Heritage Lottery Fund. It was regularly monitored during this time and sprayed with a water and chemical mix to keep it damp and to prevent mould growth.
Storage of the Shield
South Cadbury Shield Treatment
The conservation treatment of the shield began in January 1998. A box was constructed around it and gaps filled with an expanding foam to form a lightweight rigid support. This was to stabilise cracks that had appeared in the soil and prevent the shield moving as the soil around it was excavated.
X-radiography had shown that the shield was almost complete but that damage had occurred. The condition had been affected by the soil cracking and the condition of the corroded metal was varied. As well as the decoration, the x-rays revealed the existence of a hand grip.
Foam was used to support the shield
Using the x-rays, a working drawing of the shield was made. The surface was exposed in four quadrants, retaining soil and metal samples to be sent for analysis. The surface of each quadrant was gently cleaned and consolidated until the whole surface was exposed. The surface was recorded in great detail with drawings, photographs and also by taking impressions of certain preserved features during treatment.
A final year media studies student from Salisbury College was involved in filming early stages of treatment, further filming was carried out by Wiltshire County Council’s Audio-Visual Services. GKN Westlands also became involved in order to create a three dimensional representation of the shield.
X-ray of the shield
Before the shield could be turned over in order to remove the soil from the second side, several layers of backing material were applied to the exposed surface with a suitable adhesive. Gaps within the box were filled as before and a lid fixed securely. The whole box was then turned over and the second surface was excavated.
In order to successfully display the shield, it was necessary to ‘sacrifice’ one surface by building a suitable support backing. Due to its fragility, only one side of the shield could be visible whilst on display. The surface with the most technical information visible was chosen. Contextually this was also the way the shield had lain whilst in the ground.
A rigid support made from glass fibre and polyester resin was constructed to fit the profile of the shield surface. A layer of material was fitted over the top to improve the appearance of the support for display.
South Cadbury Shield Significance
The shield is 665 mm in diameter and made of sheet bronze only 0.6 mm thick. It is a British form known as the Yetholm type, named after the discovery of three shields at Yetholm in southern Scotland. Around twenty of this type of shield are known from Britain and Ireland, although this was the first to come from an excavated context in North Western Europe.
The shield after conservation
This type of shield is characterised by a central circular boss surrounded by concentric alternating lines of raised ribs and small bosses. The South Cadbury shield has 25 rows each of ribs and bosses. Other features include two ‘tabs’ rivetted to the back to enable a strap to be attached and a hand grip. This was made from a bar of bronze hammered out to the thickness of sheet metal in the centre and then folded over on itself.
The thin nature of the metal of the shield would have made it completely unsuitable for use in combat. These were objects of status and prestige and in common with later Bronze Age shields, Yetholm type shields have been found in wet conditions where they had been placed as ritual deposits. The South Cadbury shield is the only exception, being found in a dry deposit.
A number of shields have suffered damage in the form of holes or missing areas. It is not known whether this was a ritual ‘killing’ at the time of burial or damage inflicted at an earlier stage. The South Cadbury shield had been stabbed in three places.
A replica hand grip
The discovery of the shield has initiated further research into shields in general. Metallurgical analysis of the South Cadbury shield together with six others of the same type has revealed that the hand grips contained a core of pure tin. The high-tin alloy used in the manufacture of the shields also has important implications for their dating.
A bone found directly underneath the rim of the shield gave a radiocarbon date of 940 +- 110 cal. BC.
Pollen preservation was poor and revealed little about the context in which the shield was found. It did show that certain species such as lime and holly were growing near by.
Detail showing 'stab' marks found on a similar shield
The shield is now on display at Somerset County Museum in Taunton. A climate-controlled showcase with fibre optic lights to highlight the surface detail has been custom built. Visitors have 360° access to the case and displays provide information on the discovery and conservation. The shield is also used as a case study by visiting educational groups.
The Conservation Service won the 1999 Museums & Galleries Commission Award for Conservation for the treatment of the shield and the various research and outreach opportunities it produced.