A 710-year-old copy of the declaration of human rights known as the Magna Carta — the version that became part of English law — was auctioned Tuesday for $21.3 million, a Sotheby's spokeswoman said.
The document, which had been expected to draw bids of $30 million or higher, was bought by David Rubenstein of The Carlyle Group, a private equity firm, the spokeswoman said.
Sotheby's vice chairman David Redden called the old but durable parchment "the most important document in the world, the birth certificate of freedom."
The document was owned by the Perot Foundation, created by Texas billionaire H. Ross Perot, since the early 1980s. It had been on exhibit at the auction house for the past 11 days.
Bearing the seal of King Edward I and dated 1297, it is one of 17 known copies of the historic tract that defined human rights as the foundation for liberty and democracy as it is known today. It is one of two that exist outside Britain; the other is in Australia.
The Perot Foundation bought its copy from a British family for $1.5 million. From 1988 until earlier this year it was on loan to the National Archives in Washington, sharing space with the Declaration of Independence and the U.S. Constitution, two documents that drew on its principles.
"Over those years," Redden said, "it may have been seen by 40 to 50 million people, certainly the most viewed version of the Magna Carta anywhere."
The Magna Carta came into existence when a group of English barons demanded that King John affix his seal to a list of protections at Runnymede in 1215. Those edicts were not fulfilled, but subsequent versions of the document followed for the next 80 years, until 1297, when it was codified into law.
Tuesday's sale price included the auction house's commission.