Scientists at the University of London are re-examining the wax seals often used in medieval times to sign documents or ensure they were not opened, in order to see if the wax contains fingerprints.
One part of the project is to compare the fingerprints to each other -- not every seal carries prints, but enough do that some documents attested to be from the same person can be checked out to see if that's true. Another will be to compare them with modern fingerprint databases and see how unique fingerprints might actually be. The usual thought is that no one in the world has your fingerprints but you, and no one who ever lived has had them before. The older prints might prove that repetition does happen every now and again, even if spread out over a period of hundreds of years.
This may be O.J. Simpson's big chance.