Scientists read 300-year-old sealed letter without opening it "Virtual unfolding" allows researchers to look inside intricately folded historical letters without damaging them. Scientists are using technology to read centuries-old letters sealed using "letterlocking." Nature Communications In a letter, dated July 31, 1697, Jacques Sennacques asks his cousin Pierre Le Pers, a French merchant in The Hague, for a certified copy of a death notice for Daniel Le Pers. That's no revelatory request by any means, but for the past 300 years, the letter has remained sealed away, its contents unseen. Now, thanks to a technique that let scholars peek inside virtually without damaging the intricately folded historical document, Sennacques' request has been uncovered. The new technique could hold promise for unlocking sealed correspondence containing historical gems across time and place.