The BBC writes:
A manuscript once considered an unofficial copy of Magna Carta is now believed to be a genuine version and ”one of the world’s most valuable documents”, according to UK academics.
Harvard Law School paid $27.50 (then about £7) for it in 1946 and for years it has remained tucked away in its library, its true identity unknown.
But two medieval history professors have concluded it is an extraordinarily rare and lost original Magna Carta from 1300, in the reign of King Edward I, that could be worth millions.[…]
The manuscript’s purchase price of $27.50 would be about $450 (£339) in 2025, based on inflation.
BBC
It seems like Harvard Law School got a pretty good deal on that geninue copy of the Magna Carta. Of course, they didn’t know was geniune at the time of purchase or they wouldn’t have paid a petty $27.50 for it.
The article goes into a lot of detail about how they determined it was geniune and also gives a little bit of history about the document. It’s a very interesting read.