In 1676, Sister Maria Crocifissa della Concezione of the Palma di Montechiaro convent wrote a coded letter. The letter was found in her room and she had no previous recollection of actually writing it, leading her to claim that Satan had possessed her and used her hand to write it.
For over 300 years it has remained a mystery as no one had been able to decode the letter which had been written using symbols and letters that resembled aspects of Greek, Arabic, Latin, and the Runic alphabets. Sister Maria was an accomplished linguist due to her studies at the convent which had led some researchers to believe that she wrote this letter in a language of her design based on languages and symbols she was already aware of.
The LUDUM group, led by Daniele Abete, had found the code-breaking software in one of the darker corners of the web, where algorithms developed by intelligence agencies have leaked to a wider audience. After priming the algorithm with ancient Greek, Arabic, and Latin, as well as the Runic alphabet, the team fed it the text of Sister Maria's "Devil's letter."
The strategy worked: The letter turned out to be made of a jumble of languages that, when teased apart, could be read. The nun's writing indeed has a devilish bent to it. As The Times reports, Sister Maria wrote that the Holy Trinity were "dead weights" and that a basic principle of Catholic doctrine "works for no one."
Abete suspects that today the nun might be diagnosed with schizophrenia or a similar condition: Perhaps she did hear a voice dictating the letter, and her linguistic skills produced this mishmash of language and heresy.
On that morning in 1676, Sister Maria woke up covered in ink, with no recollection of writing the letter. She claimed that Satan himself had taken over her body and written the letter. The other sisters of the convent believed her.
In the 17th century, medical science was not even in the same ballpark as what we know today. Because Sister Maria wrote the letter but couldn't remember doing so, several researchers have suggested that it is possible that she was suffering from schizophrenia or bi-polar disorder, two conditions that were not defined until the last century.
The "Devil's Letter" has been on display at the convent since the 17th century and many people have attempted to decipher it over the years. This Italian team is the first to have any success, but there is much that still needs to be understood.