Preserving the Magna Carta

The Magna Carta on display at Salisbury Cathedral. This is one of the 4 surviving copies of the 1215 charter. Image: 1000 Words /

There’s a lot of work involved in preserving medieval documents.

A copy of the 1297 Magna Carta will be returning to display in the National Archives Building in the US after receiving a touch-up job. It will also be housed in an enclosed, controlled environment to protect it from light, humidity and mould.

King John of England was forced to sign the first Magna Carta by an assembly of barons in 1215. It required him to proclaim certain liberties and accept the traditional rights of the country’s free people, who could not be punished except through the law of the land.

However, the document was legally valid for three months — King John renounced it as soon as the barons left London. Pope Innocent III also annulled the agreement and released John from his oath to obey it.

After another confrontation with the Barons, King Edward I reissued the Magna Carta in 1297. Its original title (in Latin) was The Great Charter of the Liberties of England, and of the Liberties of the Forest.

It was also entered into the official Statute Rolls of England for the first time and became the foundation of English law. “Constitutionally, it’s probably the most important issue, because it’s the one that enshrines what we now regard as people’s rights under the law , even though only three of its clauses are still on the Statute Books today,” said Neil Boness, Rare Books Librarian at The University of Sydney.

Despite the fact it is written on vellum, the Magna Carta, like other medieval documents, can decay if exposed to excessive light or humidity. Although it is in better condition than the Declaration of Independence, which dates from 1776 and was exposed to sunlight for decades, the Magna Carta needed repairs. Conservators removed old patches and adhesives, and repaired small holes and tears with handmade long-fiber papers from Japan and Korea.

The document is now being kept in a controlled environment. A team of engineers from the National Institute of Standards and Technology (NIST) constructed a single block of aluminium that minimises the number of joints or spots that could create leaks. About 90 per cent of the block was cut using a three-dimensional laser scan of the document and a computer controlled milling machine to ensure a perfect fit.

The end result is 104 cm wide, 71 long and 15.2cm deep, with a nest for the original wax seal, which is attached to the document by a parchment ribbon. The case was filled with argon gas to prevent oxidation — the inks of medieval documents, which are made up of a variety of compounds including oak gall, iron filings and lead, might react with chemical impurities in the air.

If they oxidise, they can eat through the document, although this reaction would probably have taken place within 100 years. “Argon, being an inert gas, will certainly stop the oxidation,” Boness said.

The Magna Carta will return to public display in the National Archives building in Washington, DC, on February 17. Its enclosure will be placed alongside the Declaration of Independence, the Constitution and the Bill of Rights — NIST built enclosures for all of them.

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