Coded letter about conspiracy to assassinate Charles V deciphered

Monarch sent a series of symbols to his ambassador in France talking about an attempted conspiracy against his person

24 november
– 3:16 pm

(updated at 3:17 pm)

Historians pored over the secret letter code of Emperor Charles V for months

Photo: Jean-Christophe Verhaegen/AFP/Getty Images / Jean-Christophe Verhaegen/AFP/Getty Images

One secret code in a Letter of Emperor Charles V it was deciphered by a team of researchers from a laboratory in Loria, in eastern France, more than 500 years after it was sent. In a fully encrypted message addressed to his ambassador in France, the Holy Roman Emperor and King of Spain speaks of a conspiracy to commit murder against him.

Charles V is regarded as one of the most powerful individuals in all of history. Due to a series of wars and royal marriages in the 16th century, the monarch inherited and ruled a gigantic empire that encompassed much of Western Europe and the Americas for over 40 years.

Charles V’s letter, addressed to an ambassador in France, had been forgotten since 1547 and took more than six months to be deciphered by historians.

Cryptographer Cecile Pierrot first heard about the document in 2019, at a dinner, and only managed to gain access to the letter in 2021. She told reporters that, while mysterious, the letter was completely incomprehensible at first glance.

Using software to help with the investigation, researchers discovered that Charles V used over 120 symbols from different families to encrypt the message. To mislead the curious, the monarch drew icons that meant nothing, joined more than one word into a single symbol and replaced vowels that come after consonants with marks — an inspiration that probably came from Arabic.

Another letter, in which the same ambassador had scribbled a code transcription template, also helped in the process.

Emperor Charles V in period painting

Photo: reproduction

worn out relationships

Camile Desenclos, another researcher involved in the discovery, claims that the content of the letter shows a strain in the relationship between Charles V and the King of France, Francis I, in 1547. The monarchs had signed a peace treaty three years before, but there were several attempts to weaken each other.

In the letter, Charles V talks about a possible assassination plot against himself that would be unfolding in France. The historian comments that, until today, little is known about the movement, but underlines that the document makes the monarch’s fear evident.

Researchers now hope to be able to decipher more letters and thus understand more about Charles V’s strategy in Europe. “We are likely to make many more discoveries in the coming years,” said Desenclos.

Letter from Charles V dealt with assassination attempt, says historian

Letter from Charles V dealt with assassination attempt, says historian

Photo: Jean-Christophe Verhaegen/AFP/Getty Images / Jean-Christophe Verhaegen/AFP/Getty Images

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