A rare copy of the Magna Carta has been sold for $21.3m (£10.6m) in an auction at Sotheby's in New York.
The 1297 copy of the Magna Carta is the only one in private ownership
The copy dating from 1297, one of only 17 still in existence, was bought by US businessman David Rubenstein.
The auction item had been owned by American billionaire Ross Perot's Perot Foundation since 1984 and was on view at the National Archives in Washington.
The original Magna Carta was sealed by King John of England in 1215 and enshrined civil rights in English law.
Mr Rubenstein, co-founder of private equity firm The Carlyle Group, wants to put the document back on display at the National Archives.
He said: "I have always believed that the three most important documents were the Constitution, the Declaration of Independence and the Magna Carta.
"This document stands the test of time. There is nothing more important than what it represents.
"I am privileged to be the new owner, but I am only the temporary custodian.
"This is a gift to the American people. It is important to me that it stays in the United States."
'Talisman of liberty'
The auctioned copy, the only one in private hands, had been expected to fetch $20m when it went under the hammer.
The Magna Carta was not confirmed as English law until the version sealed by Edward I in 1297.
David Redden, vice-chairman of Sotheby's, described the Magna Carta as "the most important document in the world".
"The 1297 Magna Carta became the operative version, the one that was entered into English common law and became the law of the land," he said.
"The 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."
The Magna Carta came into being as the result of a dispute between King John and English barons, and it went some way towards limiting the authority of the king.
The charter guaranteed basic freedoms and property rights to those considered "free men".
Its most notable legacy in present-day English law is the principle of Habeas Corpus, which protects people against unlawful imprisonment.
Only four copies dating to the 1215 signing of the Magna Carta are believed to have survived, and all of them are in England.