It took nearly 500 years for researchers to crack Charles V’s secret code

The Holy Roman Emperor Charles V wrote a letter to his ambassador in 1547, which was written in a secret code. Charles V's fear of a secret assassination plot and continued tensions with France, despite having signed a peace treaty with the French king a few years earlier, have been revealed by researchers.

The future Holy Roman Emperor was the daughter of Philip of Hapsburg andJoanna of Trastamara. She was nicknamed "Joanna the Mad" because of her mental illness and gave birth to Charles in a bathroom in the wee hours because she insisted on going to a ball despite having labor pains. Charles had an enlarged jaw due to inbreeding and it became even worse in subsequent generations. Charles had to be carried around in a chair because of his gout, which was so severe he had to be carried around in a wheelchair.

The Holy Roman Empire spanned from Germany to northern Italy in the early 16th century and included the Burgundian states and the Kingdom of Spain. He earned the title of "the empire on which the sun never sets" after continuing the Spanish colonization of the Americas. Charles V abdicated as emperor in favor of his brother Ferdinand in 1556 as his health deteriorated. In 1557, he retired to the Monastery of Yuste.

Charles V wrote a three-page letter to his ambassador against the backdrop of a battle against the rising Protestant religion, as well as tensions with Francis I of France. Cecile Pierrot found the letter in the basement of the historic library in Nancy after hearing about it at a dinner in 2019. Pierrot tried to crack the code by grouping the symbols and looking for patterns.

The task was difficult since the symbols didn't use a symbol-to-letter representation. For instance, a needle to represent the English King Henry VIII was one of the many representations of whole words. The letter 'e' is the most commonly used letter and the code makers avoided using as much as possible. A few symbols didn't seem to do anything. Pierrot said that simply putting it into a computer and telling it to work it out would have taken longer than the history of the universe.

Thanks to historian Camille Desenclos, Pierrot was able to read several other letters written by and sent to the emperor. Pierrot said that the letter was the key to their success. Without it, we wouldn't have gotten there, but it saved a lot of time. In the future, the team hopes to identify and translate other letters between the two men.

The letter says something. Since an academic paper is in the works, Pierrot and her colleagues have not made their translation public. The letter was written after the death of Henry VIII and a rebellion in Germany by a Protestant group. According to Pierrot, Charles V wanted to keep the peace with France so that he could focus on fighting the league.

Charles V instructed his ambassador to find out as much as possible about the rumor that he was the target of an assassination attempt. There was no assassination plot uncovered. The emperor created a response to the news that his nephew had been forced to flee a rebellion in the Czech Republic. Saint- Mauris was told to spread the word that Ferdinand had left the Czech Republic to join his father on a political campaign.

Henri II succeeded his father, Francis I, after the letter was written. Protestantism in Germany and France was not stamped out by Charles V. In 1552, Henri II formed an alliance with Protestant princes against the emperor, and in 1555, Charles V agreed to the Peace of Augsburg.