A coded letter penned by the King of Spain in the 16th century has been deciphered by a team of researchers. Charles V reportedly sent the mysterious missive to his French ambassador in February of 1547. The curious letter contains three paragraphs of readable text along with portions which are comprised of peculiar letters and symbols that constituted a code that only the king's proverbial inner circle could understand. At some point in the centuries since the message was sent, it wound up in the Stanislas Library in the French city of Nancy. Remarkably, the intriguing note went unnoticed in their archives until two years ago, when it was unearthed and inspired a group of researchers to find out what the code might say.

The team, which consists of three cryptographers and a historian, announced their findings at a press conference late last month. The explained that the process proved to be difficult as the symbols stood in place of complete words rather than just individual letters and that they were interspersed with marks that served no purpose except to confuse anyone trying to decode the king's message. However, using complex computer algorithms as well as a previously decoded letter from the same ambassador during that era, the team were able to completely decipher the missive after a painstaking six months of work.

The contents of the message itself are not particularly salacious or revelatory and are more of a glimpse into the mindset of Charles V at the time that he wrote the letter. Specifically, he muses about his country's state of relations with France and England, while worrying about rumors of an assassination plot which ultimately never came to fruition. Reflecting on the uniqueness of their accomplishment in deciphering the coded letter after it had remained secret for so long, team member Camille Desenclos marveled that "it's rare as a historian to manage to read a letter that no one had managed to read for five centuries."