What is the price of freedom and democracy? The world is about to find out when one of the versions of Magna Carta, which first enshrined the authority of the people over their monarch, is auctioned in New York.

Sotheby’s announced yesterday that the 2,500-word manuscript – “the most important document ever ffered at auction” – will be presented for sale in mid-December. It is expected to fetch up to $30 million (£15 million).

It was at Runnymede in 1215 that the unpopular King John was forced to set his seal to Magna Carta or “Great Charter” by a group of rebellious barons and churchmen. Much of what he agreed to is now seen by historians as reactionary, preserving the power of the barons rather than liberating the people from tyranny.

However, it also established the principle that no man is above the law and was a formative influence on the later development of British parliamentary democracy and the American independence movement.

Magna Carta compelled the King to renounce certain rights, respect specified legal procedures and accept that his will could be bound by the law. It also introduced ideas that would later be interpreted as the right to a speedy trial, the right to a trial by a jury of one’s peers and the right to protection from unlawful imprisonment.

The document was revised and reaffirmed throughout the 13th century. Seventeen versions from this period survive: four from the reign of John, eight from Henry III’s time and five from Edward I’s. The oldest copies are in the British Library, in London, Lincoln Castle and Salisbury Cathedral.

Sotheby’s copy was endorsed by Edward I in 1297, the year that Magna Carta was confirmed as English law. It is the only one in private hands and one of only two held outside Britain (the other belongs to the people of Australia).

The manuscript has been displayed for the past 22 years in the National Archives in Washington, with the Declaration of Independence and the Constitution of the United States.

It was on loan from the Perot Foundation, which now intends to sell it to raise funds for “medical research, improving public education and assisting wounded soldiers and their families”.

Ross Perot, the Texan billionaire who twice ran for President in the 1990s, bought Magna Carta for $1.5 million in 1984 from relatives of James Thomas Brudenell, the Earl of Cardigan, who led the Charge of the Light Brigade during the Crimean War.

He said at the time that it was like finding the Mona Lisa for sale.

The document had been in the Brudenell family since between the 14th and 16th centuries but later generations had been unaware of its importance. It was “discovered” in 1974 during an inventory of the family’s estate at Deene Park, Northamptonshire.

David Redden, the vice-chairman of Sotheby’s, said yesterday: “Magna Carta is the first rung on the ladder to freedom. This document symbolises mankind’s eternal quest for freedom; it is a talisman of liberty.”

Secrecy surrounded the preparations for the sale. James Zemaitis, the director of Sotheby’s 20th-century design department, was not told why he was being asked to give up a room that he had reserved for a preauction exhibition, The New York Timesreported.

“All they told me was, ‘David Redden is selling this really important document. Can you give up this room for us?’” he said. “I’m like, ‘Sure, but what is he selling – Magna Carta?’”

Signed and sealed

— Magna Carta was agreed at Runnymede, near modern-day Staines, Surrey, on June 15, 1215

— On August 24, 1215, Pope Innocent III issued a papal bull declaring Magna Carta null and void. It had been legally valid for just ten weeks

— It was revised and reissued in 1216 and 1217, and again in 1225

— Benjamin Franklin, Thomas Jefferson and John Adams cited George III’s refusal to grant the American colonies the rights enshrined in Magna Carta as justification for the independence struggle

Sources: British Library, Times archives

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