Rubenstein, right, shows off his copy of the Magna Carta. (Associated Press photo)

Over at Housing Complex, Lydia DePillis filed a dispatch from an event earlier today that we’re still kicking ourselves for missing:

David Rubenstein, the billionaire co-founder of the Carlyle Group, unveiled today at the National Archives his original copy of the Magna Carta. Besides using his philanthropy to encourage panda reproduction and plug the cracks in the Washington Monument, Rubenstein loves collecting ancient documents. And beyond the Rosetta Stone and Dead Sea Scrolls, it doesn’t get much bigger than the Magna Carta, the 13th-century edict that was the first example of an English monarch’s royal powers being curtailed by his subjects.

Oh, sure, in the 793 years since it was issued, practically ever precept of the charter has been superseded, but it laid the groundwork for the common law that has governed the English-speaking peoples ever since.

It is unknown just how many copies were originally produced, but Rubenstein, DePillis reports, paid $23.1 million for his when he bought it. But that’s not the only significant document he’s collected:

He owns the Emancipation Proclamation, which hangs in the Oval Office. He’s got the first map of America, on loan to the Library of Congress

Rubenstein’s copy of Magna Carta, after being carefully restored by the Archives’ staff, now sits in a gas-filled aluminum case valued at $322,000. It goes on display February 17.