WASHINGTON (AP).- A 715-year old copy of Magna Carta will soon return to public view at the National Archives after a conservation effort removed old patches and repaired weak spots in the English declaration of human rights that inspired the United States' founding documents.

The National Archives unveiled the medieval document Thursday in a specially humidified glass and metal case. It is the only original Magna Carta in the United States and will return to public display Feb. 17.

A $13.5 million gift from philanthropist David Rubenstein funded the conservation, the custom-built case and a new gallery being renovated to host Magna Carta. Rubenstein bought the historic document at auction in 2007 for $21.3 million and sent it to the National Archives on a long-term loan.

Rubenstein, a co-founder of the private equity firm The Carlyle Group, said he sought the document previously owned by Texas billionaire H. Ross Perot because he wanted to keep it from leaving the country.

As a history buff, Rubenstein has become an expert on Magna Carta's legacy dating to 1215. That's when noblemen came together to declare their rights to King John, including the first limits on arbitrary taxation that led to the principle of "no taxation without representation" and the right to a trial by jury.

"This became something that set the trend for common law" in Britain and later in the United States as founding fathers referred back to Magna Carta, Rubenstein said. "If you read the early writings of Hamilton and Jefferson and Adams and Madison, many times they say it's because of the Magna Carta that we're doing this."

There are 17 surviving copies of Magna Carta. Fifteen are in Britain, and one is displayed at Australia's parliament.

The U.S. copy was one of four reissued in the year 1297. It still carries the wax seal of King Edward I of England, which is attached by a ribbon under the document. The 1297 document became the law of the land in England.

It's central to the founding of the United States because the colonists argued they were entitled to the rights under Magna Carta as Englishmen, Rubenstein said. But King George disagreed, so the colonists chose to break away.

Magna Carta was far ahead of its time in opening the door to principles for government based on law and the role of the people, said American University law professor Stephen Vladeck.

"It's really the first example, at least in Western history, of a monarch agreeing to abide by legal rules written by others," Vladeck said. "So we really have the Magna Carta to thank for the legacy of what we could call in American law due process — the idea that the government should act fairly and should act at least rationally in all cases."

Rubenstein's gift is funding an exhibit that will open in 2013. There, Magna Carta will be shown as a forerunner to the freedoms envisioned in the U.S. Declaration of Independence, Constitution and Bill of Rights and will be paired with other documents declaring human rights for African Americans, women, immigrants and others.

Remarkably, this Magna Carta is in better condition than the much younger Declaration of Independence from 1776. The ink is dark and legible, though written in medieval Latin, while the handwritten words of the Declaration of Independence faded badly years ago.

That's because the Declaration of Independence was rolled up frequently for travels and for decades was exposed to sunlight while on public display near a window, according to National Archives records.

This Magna Carta was folded up for centuries, likely in a cool, dark place at a family home in England. It was also written on parchment — a specially prepared animal skin — rather than on paper.

"It's in remarkably good condition," said Kitty Nicholson, the Magna Carta's lead conservator at the National Archives.

Still, the document required repairs.

Over the past year, conservators removed old patches and adhesive that had caused it to contract. They repaired small holes and tares with handmade long-fiber papers from Japan and Korea that were toned to match the parchment. Those patches were applied with a mixture of gelatin and wheat starch paste, Nicholson said.

Now the document is sealed in a 225-pound case filled with humidified argon gas to prevent degradation from oxygen and will be lit with filtered light, removing ultra-violet rays and some radiation. The document rests on cotton paper produced at the University of Iowa Center for the Book to give it a soft, acid-free surface.

"Once it's sealed in this encasement, we want it to rest in a relaxed format and not contract or do anything to change," Nicholson said.

A new interactive display will allow visitors to zoom in on an image of the parchment and see areas that were repaired. Some words had been hidden by water damage in the past. But an ultraviolet photograph taken during the conservation work reveals the words are still there, though invisible to the naked eye.

Visitors can read an English translation of Magna Carta's Latin words and compare it with language in the Constitution and Declaration of Independence.

Rubenstein said he became interested in the ideas behind the Constitution while working for the Senate in his 20s, which led him to study the Magna Carta. He has purchased other historical documents, including a copy of the Emancipation Proclamation on loan to the Oval Office.

"Everybody in life has certain things that they like, and I guess one of the things I like is buying these documents and owning them," Rubenstein said.

But he said he has no interest in displaying the documents in his own home, adding he hopes Americans will learn more about history from such public displays.

Magna Carta will likely remain at the National Archives permanently, added Rubenstein, now 62.

"You can't be buried with these documents as far as I know."



Copyright 2012 The Associated Press.