A rare copy of the Magna Carta dating from 1297 has sold for £10.6 million ($21.3 million) at an auction in New York.

Sotheby's sold the document to US businessman David Rubenstein, co-founder of the Carlyle Group, after it was placed up for sale by the Texas-based Perot Foundation, of US billionaire Ross Perot.

One of just 17 copies of the famous treaty still in existence, the copy of the Magna Carta sold at Sotheby's is the only one in private hands. It was owned by the Brudenell family, earls of Cardigans for five centuries before being sold to Mr Perot for around $1.5 million.

Owned by the foundation since 1984, the Magna Carta copy had been on display in the National Archives in Washington and was estimated to sell for between $20 million and $30 million. Handwritten in Latin on animal-skin vellum, the 2,500-word manuscript has the wax seal of King Edward I of England, grandson of King John.

Sealed by King John of England in 1215, the original Magna Carta, or Great Charter, was a royal agreement between the king and the English Barons. The charter outlined civil liberties and has been used as the basis for a number of pieces of legislation, such as the US Constitution and the Universal Declaration of Human Rights.

Mr Rubenstein has declared that he plans to place the document on display in the National Archives alongside the US Constitution and the Declaration of Independence.