The Ultimate Vampire Resource and Directory

"The story begins at the Palma di Montechiaro monastery in Sicily. Born in 1645, Isabella Tomasi entered the Benedictine convent in 1660 and became Sister Maria Crocifissa della Concezione. According to the legend, she awoke one morning in 1676 and found herself covered in ink with a mysterious letter in front of her in her handwriting but undecipherable. Since she had no memory of writing it, she claimed it was a message from Satan which she transcribed while possessed. Since no one could come up with a better explanation, the text was called ‘the devil’s letter’ and put on display at the convent where it has defied decoding for 341 years."

From the following link: https://mysteriousuniverse.org/2017/09/mysterious-devils-letter-decoded-with-help-from-dark-web/

Is the writing from a demonic possession, mental illness, or intentional manipulation by the nun?

The letter has been decoded, but it took 341 years.