By Richard Pyle, THE ASSOCIATED PRESS NEW YORK - In the year 1215, a group of English barons handed King John a document written on parchment. Put your royal seal on this, they said. John did, and forever changed the relationship between the monarchy and those it governed. The document was the Magna Carta, a declaration of human rights that would set some of the guiding principles for democracy as it is known today. While that original edict was initially ignored and John died the next year, its key ideas were included in other variations over the next few decades, most notably the right of Habeas Corpus, which protects citizens against unlawful imprisonment. More than 800 years later, about 17 copies survive, and one of those, signed by King Edward I in 1297, will go up for sale Dec. 18 at Sotheby's. The document, which Sotheby's vice chairman David Redden calls "the most important document in the world," is expected to fetch a record US$20-30 million. While earlier versions of the royal edict were written and then ignored, Redden said, "the 1297 Magna Carta became the operative version, the one that was entered into English common law and became the law of the land," ultimately effecting democracies around the world. Today, its impact is felt by perhaps a third of the world's people, he said. This includes all of North America, India, Pakistan, much of Africa, Australia and other areas that made up the British Commonwealth. "When it's something as enormously important as this, you try to get a handle on it," he said. "It is absolutely correct to say the Magna Carta is the birth certificate of freedom. It states the bedrock principle that no person is above the law - that is the essence of it." Only two copies of the Magna Carta exist outside Britain, one in Australia and the one Sotheby's is auctioning off. An earlier Magna Carta version was loaned by Britain to the United States for its bicentennial celebration in 1976, but suggestions that it be made a permanent gift were rejected. The 1279 Magna Carta was forced on Edward I by barons unhappy over taxes imposed to pay for his military campaigns in France, Wales and against Scottish rebel William Wallace. The levies were approved in the king's absence by his 13-year-old son, Prince Edward. Written in medieval Latin on sheepskin that after 710 years remains intact and legible, the 1297 Magna Carta was owned for five centuries by a British family that put it up for sale in the early 1980s. From 1988 until a few months ago, it was exhibited in a custom-designed, gold-plated container at the National Archives in Washington, a few feet from its direct descendants, the Declaration of Independence and the U.S. Constitution. "As the only non-American document in there, many would love to see it go back" on display, said Redden, who will wield the hammer. He said the auction will be open to the public, but being a single lot sale, might not take longer than five minutes. On the Net: Sotheby's: http://www.sothebys.com (http://cnews.canoe.ca/CNEWS/World/2007/12/07/4712853-ap.html) This photo released by Sotheby's shows a copy of the Magna Carta.