Four Score and Twenty Centuries Ago

Ed Morrissey noticed this slip in Obama's speech introducing his new Supreme Court nominee:

“Of the many responsibilities granted to a president by our Constitution, few are more serious or more consequential than selecting a Supreme Court justice. The members of our highest court are granted life tenure, often serving long after the presidents who appointed them. And they are charged with the vital task of applying principles put to paper more than 20 centuries ago to some of the most difficult questions of our time.”

As Ed points out, that puts the birth of our Constitution somewhere around 9 AD. He doesn't mention in which one of the 57 states the Constitution was written.