Letterlocking

Environmental & Science Education, Society, Culture 

Ed Hessler

There was a time before there were envelopes for letters. "Hundreds of years ago," writes the BBC's Richard Fisher, "people developed ingenious methods to secure their letters from prying eyes--and they did it with only paper, adhesive and folds." 

Fisher begins his essay with a letter of Mary Queen of Scots, who in prison, February 8, 1857, wrote her last letter to her brother-in-law. When finished, to keep others from snooping, she "sealed" the letter by making a spiral lock.  The lock was made from a thin strip of paper cut from the margin. She poked the knife through the small rectangle she had made from the letter and then fed the strip through it, looping and tightening it a few times. Her brother-in-law would know whether the letter had been read before he received it if the strip had been ripped. Envelopes were not in use because paper was scarce and expensive. 

Fisher's essay includes a video on how Mary Queen of Scots locked her letter from prying eyes.

Her letterlocking technique was among many techniques developed. Their discovery "began when the conservator Jana Dambroglio was leafing through a cache of documents in the Vatican Secret Archives in Italy" where she was on assignment. She noticed a variety of cuts, creases and folds in many of the papers and took methodical notes and made models of a few. When she returned to the United States  she took her notes and models with her she and with a colleague sought more. One of the finds is a "trunk full of 2600 letters from 17th-Century Europe which had gone undelivered--577 of which were unopened.

She and a colleague have found "at least 18 different formats," noted various attributes (slits or tucks) and rated the security of the various locks.

Fisher decided to try it in a workshop and there is a video demonstration you can use to try to make the lock triangle. He also includes diagrams of two others the team has identified. One of these is, in Fisher's words, "a true folding challenge" and is known as the "dagger trap." There is a video walk through that may help if you try it. This fold "was essentially boobytrapped," i.e., it "appeared to be a simple pleated letter from the outside" but inside there was "a hidden strip of paper inside that 'trips' when opened, revealing it had been unlocked."