Magna Carta Lincoln Exemplar – Conservation and Management Case Study
Introduction
This case study describes in a very brief summary the steps taken to manage the care and conservation of the Lincoln exemplar of King John’s Magna Carta of 1215 and related charters owned by the Corporate Body of Lincoln Cathedral.
Magna Carta is more than just a document. Since its first iteration nearly 800 years ago it has become an icon that embodies mankind’s aspirations for universal human rights and liberties. In addition to being considered a cornerstone of English law, it holds a position of highest legal and social significance in countries throughout the world, as evinced most recently by its addition to UNESCO’s Memory of the World International Register. With its associated Charter of the Forest, it also has a modern relevance in promoting the protection of the natural environment and sustainable use of land, woodlands in particular.
All owners of the four remaining 1215 copies of Magna Carta (British Library, Salisbury Cathedral and Lincoln) have been obliged, through the document’s wider public significance, to display their respective copies either permanently (Salisbury) or under a rotation policy (BL and Lincoln). Alone of these institutions, Lincoln has a policy to loan its copy to other nations, most commonly the United States where Magna Carta has especial significance as the basis for the US Constitution and Bill of Rights.
The loan of an iconic treasure such as Magna Carta requires a higher level of understanding of its nature, condition and vulnerability than does the static display in the custodian’s own institution. The Dean and Chapter of Lincoln Cathedral have recognised this greater need for detailed knowledge about its Magna Carta by commissioning Conservation Ltd to provide expert conservation assessment and support, leading to the highest levels of protection and a considerably greater depth of information about its condition than has hitherto been assembled.
The worldwide interest and access to this document has led directly to improvements in knowledge and care and has provided the impetus for major investment in a new gallery for its display in time for its 800th anniversary in 2015. In the process, Lincoln Cathedral has grown to understand that scientific and historical knowledge about the Magna Carta exemplars and about the display requirements for early manuscripts could be improved and is collaborating with Conservation Ltd and University of the Arts London to develop research into these matters. The aim is to maximise the social and educational outreach potential of Magna Carta and to improve knowledge for the benefit of all custodians of popular manuscripts, to ensure that regular public access is possible in the safest manner.
Conservation and Management of Magna Carta
In 2006, Chris Woods was approached to advise on the condition and care of Lincoln Cathedral's Magna Carta and assist in planning a loan to a venue in Virginia USA. The work since then has ranged from detailed conservation examinations, recording, loan couriering, installation and re-display to the development of an institutional preservation and access policy and articulation of risk and benefit analysis for exhibition lending.
Although widely loaned and toured in the past, this copy had not been out of the country since the late 1980s when it toured the US and was exhibited in Australia. It was mounted within an open fronted parchment ‘envelope’ inside a sealed container consisting of aircraft glass back and front. This in turn was housed inside a purpose built exhibition case. It had been mounted in parchment and glass in 1976 by the then Science Officer of the British Museum, David Baynes-Cope, in preparation for a loan the US at the time of the independence bicentennial. Parchment is strongly hydrophilic – it absorbs and loses atmospheric moisture readily, expanding and contracting respectively to a significant degree even under small changes in relative humidity (RH). It is possible that the glass enclosure was intended in part to reduce external changes in humidity reaching the document, and probably also to reduce atmospheric pollutant contamination.
The document was first examined under glass. The glass enclosure was sealed with an epoxy-resin-like adhesive coating, but it appeared that the seal was no longer complete as some places had fissures. The exhibition case and the room in which it was housed had no temperature control, so the RH conditions experienced by the document inside its enclosure had fluctuated throughout its time in this location, leading to a pattern of distortion caused by restrictions from the parchment mount. The latter was probably expected to expand and contract in sympathy but this was an error since the front border of parchment was adhered, with starch paste, to the back sheet. The adhesion of these layers meant that the border was expanding against the direction of expansion of the document, causing the latter to ‘ripple’, especially from the corners inwards, as can be seen in figure 1. In addition a small part of the top edge was later found to have become adhered to the document, which would also have contributed to distortion.
Mr Woods undertook a risk assessment to help the owners and custodians to decide whether or not to remove the document from this enclosure. The decision was made to remove it, to carry out a detailed condition assessment and report, including systematic digital image mapping of the document, both as a record of it current condition and to provide a means of comparing its condition after loans and displays. A display specification was also provided and set of loan criteria that the owners and borrowers would use to ensure its safe exhibition.
Figure 1. Magna Carta inside glass enclosure Figure 2. Under transmitted light. Old
and parchment mount, 2006. repairs on the reverse are clearly visible.
The glass enclosure was opened and removed and the parchment mount lifted away from the document. The surface characteristics of the document were examined minutely and the condition of both parchment and ink recorded. It was notable that there were very significant changes that had happened before the creation of the glass enclosure, including ink loss in areas and the application of at least two generations of repair patches. A record of previous conservation measures was sought with the help of the Cathedral’s librarian but only limited information was available at the time, leading to Mr Woods’ recommendation that, over time, a systematic exploration of the document’s history of care should be undertaken, in order better to understand its condition. Two very small repair patches were tested and removed from the rear of the document, but a larger patch left in place. A large area of pared-parchment lining was tested but left undisturbed as it was considered that any attempt at removal would risk damage to areas already badly damaged in the past through poor conservation procedures undertaken in the 1930s and 1950s.
In order to minimise expansion and contraction of the parchment during displays and risk additional ink loss, an air-conditioned case was commissioned, operating with a set point at 50% RH ±2% and with a continuous temperature of 18º C. Condition reports began to be produced by Mr Woods before and after each loan and a file of environmental records was created. Light levels were initially set at a maximum of 50 lux but when the level of demand for the document became clear this was reduced to 25 lux and a rotation schedule be considered. Existing lighting recommendations such as BS5454:2000 were recognised to be unclear. A research project to determine more precisely the rate of change to iron gall inks under exhibition lighting was proposed. If funding is secured this will be undertaken between 2010 and 2012 and it is intended that a straightforward method of recording such manuscripts should be defined to assist archivists and conservators to plan for exhibition of documents in a more informed way. In the meantime, with sponsorship from Rotronic Ltd, following an approach by Mr Woods, a high quality RH and temperature sensor was installed in the case and allowed conditions to be viewed from the UK in real time online from anywhere in the world. This mechanism has now worked during two successive US loans to Los Angeles and New York.
Figure 3. Magna Carta inside its air-conditioned case.
The sensor probe is visible above the charter.
For regular display at Lincoln Castle, passive control cases were commissioned for Magna Carta and for its sister document the Charter of the Forest of 1217. These used pro-sorb silica gel cassettes to condition the space around the charters from underneath the vitrine base. Following guidance from Dr David Thickett at English Heritage, the air space that permits the silica gel to work was built to be 25mm around the vitrine base. Standard guidance is 15mm, but Dr Thickett had convincingly demonstrated that this was insufficient. The new cases for Lincoln Castle have been found to be very successful using this wider gap. In addition they are constructed to guidance from the National Security Adviser for the Government Indemnity Scheme, under which these documents are covered when on continuous loan to the Castle.
In its air-conditioned case, Magna Carta is attended by an armed guard around the clock, but nevertheless it was recognised that Baynes-Cope’s logic of holding the document inside an enclosure for security and protection, especially in emergencies, remained sound. In addition, while it was anticipated that a passive display case would maintain RH conditions, a further level of stability would be achieved by having the document inside its own enclosure or ‘frame’, inside the display case. A new frame for use inside the passive case was commissioned and built to Mr Woods’ specification, and an identical frame was built for Charter of the Forest. These each consisted of aluminium ‘picture’ frame in four mitred lengths, fitted together at the corners with steel brackets. Three of the lengths were also adhered together at the corners using a neutral curing silicone sealant (allowed to cure for 28 days to release gases), with the base (acrylic sandwiched between aluminium) and the ‘glass’ (heavy-duty low-reflective, UV-screen coated shatter-proof acrylic sheet) adhered into place at the same time, making a fixed unit with one open side. The fourth side of the frame had its edges coated with the silicone, moulded and cured to the form of the corresponding mitres and edges, so that when it was slotted into place it sealed (suggested by Stuart Welch of Conservation-By-Design Ltd). Inside this unit was placed a bespoke polypropylene (Corex) sandwich containing Pro-sorb beads, and a layered support for the document, consisting of expanded polyethylene (Ethafoam) and archival cotton rag mount board. To allow the frame to be viewed at an angle Magna Carta was initially hinged to the mount board with two 7mm-wide spider tissue strips attached with gelatine to the old repair lining on the reverse. The same applied to Charter of the Forest, which also has large areas of repair parchment from treatment undertaken in the 1970s. This approach to mounting inside the frame will be reviewed when Magna Carta is next placed on display at the castle, to find a simple way of avoiding the use of hinges.
Figure 4. Charter of the Forest 1217 in its Figure 5. Magna Carta in its new display
new display frame. The small metal ‘button’
is a TempIT Rh and temperature sensor.
The advantage of a display frame that can be opened is that the charter can be removed for microscopic digital imaging used to examine the condition of the inks and areas of weakness in the parchment. A logger was placed inside the frame and the temperature and RH stability and access allowed this to be downloaded periodically. A close examination happens before and after each loan, using cold lighting with UV content below the recommended maximum 75mW/lumen. With a digital microscope using magnification at 60x and 90x, measurements can be taken on-screen to assess whether tears or ink fragments are changing (there have been no visible changes since the first of these records were made in 2007).
Close inspection reveals the manner in which inks have aged and lost over 800 years. This copy of Magna Carta was ‘re-discovered’ in 1806 in the archive of Lincoln Cathedral by the Public Records Commissioners during their tour of England identifying and cataloguing documents of public importance in private hands. At that time it is likely that it was folded and it may even have had its seal, although early published accounts do not make this latter point clear. During the 19th century it would have been given a lot of attention, possibly regularly unfolded and refolded and eventually it is believed to have been placed on display in some form. The damage that occurred during that period can be seen along the folds of the upper half of the document, where it has become split and abraded. The lower half of the document is slightly stronger parchment, being closer to the edge of the sheepskin membrane, so much of this damage is confined to the upper half. The thicker deposits of ink have in places lost fragments, and these along with the weakened parchment can be used as points to monitor change if any occurs.
Figure 2. 60X images of a capital on the dorse and a tear at one of the seal-cord holes
Working closely together, and with the expert assistance of Lincolnshire County Council’s heritage service, Lincoln Cathedral and Conservation Ltd are endeavouring to maximise access to this icon while ensuring that it is cared for to the highest level possible.
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