A copy of the Magna Carta that dates from 1297--the only copy of the Magna Carta in the United States--was auctioned by Sotheby’s yesterday, fetching $21.3 million from David Rubenstein, a lawyer and founder of the Carlyle Group. And it looks like it will be going “home.” "I am really just a temporary custodian," said Rubenstein , who intends to return the document to the National Archives in Washington, D.C., where it had been on display previously.