Wax visible inside the skull before treatment

Background

The 2009-2010 project to conserve 300 items for the new display at the Roman Baths Museum included a variety of materials from Roman earthenware ceramics to bronze statuettes. Some of the larger objects were made of lead and included lead piping from the baths themselves and a Roman coffin. The coffin was the feature of our last blog and we’d like to follow on from this with details of the conservation of the coffin’s contents.

The coffin was discovered in 1999 at the St Swithuns' Yard site on Walcot Street, Bath. The original excavation and conservation work was undertaken by the Museum of London and the project was filmed as part of the BBC series ‘Meet the Ancestors’ with Julian Richards. The coffin was buried in the late 4th century. Inside, they found a skeleton belonging to a male, approximately 45 years old.

Once excavated, it was found that the shape of the coffin had been distorted during the burial and parts of the skeleton had been crushed. Some of the bones were missing and the skull was found to be almost complete but had broken into a large number of fragments. As part of the ‘Meet the Ancestors’ programme for the BBC, a specialist in human remains, known as an Osteoarchaeologist, was asked to study the skeleton and reconstruct the skull. The reconstructed skull was made from clay and used to recreate the physical features of the buried man. 

Condition of the skull...

 
In order to reconstruct the skull for the BBC, the fragments were held together with an opaque wax which had been liberally applied to each fragment. The wax was a temporary solution to hold the skull fragments together while a cast of the skull was made and over time, the wax eventually lost its adhesive qualities and the fragments started to separate from each other. The application of the wax was not very precise and the excess wax had not been removed. There were droplets of wax spilt over the surface of many of the fragments. Where fragments of skull were missing, some areas were completely filled in with wax. This was particularly true of the lower jaw attachment where a large amount of wax was used to hold the mandible in position. The wax was applied to the join and then a second layer for added security. Where the wax had lost purchase, skull fragments had been reattached with Sellotape which over a period of time had partially stained the surface.

The wax had yellowed since the application and its sticky surface had attracted dust and dirt. When the conservators at the Wiltshire and Swindon History Centre received the skull, it was in 43 broken fragments and all of the fragments had a covering of this dense layer of discoloured wax. The broken fragments ranged from being very small, the size of a 5 pence piece, to the largest section of the face which held the cheek bones, eye sockets and nose intact.

 Wax and Blu-tack® visible on the lower jaw before treatment

The skull fragments had a layer of dust on the surface and there were some areas of soil which had not been cleaned off since the excavation. Some fragments had a layer of pink sediment paste smeared onto the surface. The surface of the bone was relatively smooth and there were a few areas of discolouration On the whole, the bone had a good physical structure with a strong, well defined internal matrix. The condition of the bone was important as it needed to be stable enough to hold its own weight once it had been reconstructed. The skull had retained most of its teeth, but two front teeth and one molar were missing. Most of the teeth sat loosely in their sockets and a number of them had been secured with Blu-tack® or wax. There was one socket which had been filled with tin foil.

Conservation Treatment…

A Conservator mapping out how the skull fragments fit together and assessing their condition.

A map was drawn up of how skull fragments related to one another and each fragment was plotted. The skull fragments would have been difficult to piece together once the wax had been removed and so the plotting was carried out first. The map also helped to ensure every fragment was cleaned and it saved time when piecing the fragments back together.

Skull fragments mapped out before treatment                                                                

Treatment began with gently cleaning off the dust and dirt from the surface. Under a microscope, the dense layers of wax were softened so that it could be removed mechanically.

A Conservator removing a large wax deposit from inside the skull                                          

The loose teeth were removed to clean off the Blu-tack® from inside the sockets. It was not possible to remove all the teeth as they were wobbling but still attached. The removal of Blu-tack® from inside the sockets was done as far as possible without causing damage to either the socket or the tooth. The teeth were then secured in place with an adhesive.

The upper row of teeth after conservation             

Japanese tissue is used in conservation as a patch or a filling material to add strength to a join and is a hand-made, thin, strong paper made from vegetable fibres. The conservator dyed the Japanese tissue to match the colours found in the skull and secured it over the join.

Inside the skull before patching with coloured Japanese tissue

Inside the skull before patching with coloured Japanese tissue

Securing the lower jaw to the skull had to be approached differently, as the jaw is intended to move independently from the skull. The jaw is intended to move back and forth within its socket at the base of the skull and is held in place with muscle tissue. The muscle tissue had been lost from the skull, leaving a void where the muscles would have held the jaw in place. Attaching the mandible to the socket could be achieved but without additional support, the adhesive join would eventually break under the strain of carrying the weight of the bone. The Japanese tissue fill would not be a strong enough support to hold the mandible in place. Therefore, the empty space was filled with a different material which would have more inherent strength and would be able to hold the weight of the jaw.

Side view of the skull after conservation

Skeleton on display



The complete skeleton on display

The conservation of the coffin lining and skull were part of the museum’s 5 year development plan to redisplay and reinterpret the collection. The skeleton and the lead coffin as well as a number of other items conserved by the team at the History Centre are now on display entitled ‘Death’ at the Roman Baths Museum.

Kelly Abbott

With thanks to Sue Fox, Curator, Roman Baths Museum.