Spain’s Emperor Charles V’s secret code cracked after five centuries

A team of researchers has cracked a five century-old code which reveals a rumoured French plot to kill the Holy Roman Emperor and King of Spain Charles V.

Spain's Emperor Charles V's secret code cracked after five centuries
The letter from Charles V to Jean de Saint-Mauris had languished forgotten for centuries in the collections of the Stanislas library in Nancy. Painting: Jakob Seisenegger (1532), Photo: JEAN-CHRISTOPHE VERHAEGEN / AFP

Charles was one of the most powerful men of the 16th century, presiding over a vast empire that took in much of western Europe and the Americas during a reign of more than 40 years.

It took the team from the Loria research lab in eastern France six months to decipher the letter written in 1547 by the emperor to his ambassador in France.

The tumultuous period saw a succession of wars and tensions between Spain and France, ruled at that time by Francis I, the Renaissance ruler who brought Leonardo da Vinci from Italy.

The letter from Charles V to Jean de Saint-Mauris had languished forgotten for centuries in the collections of the Stanislas library in Nancy.

Cecile Pierrot, a cryptographer from Loria, first heard of its existence at a dinner in 2019, and after much searching was able to set eyes on it in 2021.

Bearing the signature of Charles V, it was at once mysterious and utterly incomprehensible, she told reporters on Wednesday.

‘Snapshot of strategy’ 

In painstaking work backed by computers, Pierrot found “distinct families” of some 120 symbols used by Charles V.

“Whole words are encrypted with a single symbol” and the emperor replaced vowels coming after consonants with marks, she said, an inspiration probably coming from Arabic.

In another obstacle, he also used symbols that mean nothing to mislead any adversary trying to decipher the message. The breakthrough came in June, when Pierrot managed to make out a phrase in the letter, and the team then cracked the code with the help of historian Camille Desenclos.

“It was painstaking and long work but there was really a breakthrough that happened in one day, where all of a sudden we had the right hypothesis,” she said.

Another letter from Jean de Saint-Mauris, where the receiver had doodled a form of transcription code in the margin, also helped.

Researcher at the French National Institute for Computer Science Research (INRIA) Cecile Pierrot (L) and senior lecturer in modern history Camille Desenclos (R) explain the decoding process of an encrypted letter from Charles V, known as Charles Quint, the Holy Roman Emperor and Archduke of Austria, dated back to 1547, at the Stanislas library in Nancy, northeastern France, on November 23, 2022. – Researchers in computer science, a cryptographer and a historian decrypted the letter from Charles V dating back to the 16th century. (Photo by Jean-Christophe Verhaegen / AFP)

More discoveries to come

Desenclos said it was “rare as a historian to manage to read a letter that no one had managed to read for five centuries.”

It “confirms the somewhat degraded state” in 1547 of relations between Francis I and Charles V, who had signed a peace treaty three years earlier, she said.

But relations were still tense between the two, with various attempts to weaken each other, she said.

So much so that one nugget of information revealed was the rumour of an assassination plot against Charles V that was said to have been brewing in France, Desenclos said.

She said “not much had been known” about the plot but it underlined the monarch’s “fear”.

The researchers now hope to identify other letters between the emperor and his ambassador “to have a snapshot of Charles V’s strategy in Europe”, she said.

“It is likely that we will make many more discoveries in the coming years,” the historian said.

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Why do Spain’s civil guards wear those strange hats?

If you’ve ever seen Spanish national day parades on October 12th, then you’ve most likely seen groups of Spain’s Civil Guards marching along wearing strange black hats. What’s the reason behind this odd uniform attire and where did they originate?

Why do Spain’s civil guards wear those strange hats?

Known as the tricornio, this type of hat is one of the most representative symbols of the Spanish Civil Guard and has been a true piece of their identity for as long as most people can remember.

The main characteristic of the hat is that it has three points. Today, the hat is black, rounded at the front, while at the back is a kind of headboard with two points or wings jutting out either side. Although this is what it looks like in the modern day, its material, shape, size and its colors have evolved over time.

Origin of the tricornio

The origin of this quirky hat goes back to almost the very founding of the Civil Guard. The tricornio became part of the Civil Guard uniform in 1859, only 14 years after it was formed.  

The first ones were made from felt and were the brainchild of the Duke of Ahumada (1803 – 1869), a Spanish Army officer known for being the founder of the Civil Guard and its first director-general. He wanted to make sure the uniforms were both elegant and authoritative, yet with a showy appearance.  

READ ALSO: The tiny island that is Spanish for half the year, and French the other half 

He presented General Narváez, head of the Civil Guard at the time and the 1st Duke of Valencia, with a mannequin dressed in the uniform and topped with the tricornio hat, to be worn by the cavalry forces.

This uniform was accepted, but on the condition that the infantry forces also wear it. It was Queen Isabel II, at the proposal of General Narváez, who ruled that the tricornio should be worn by both.  

At the time, it was a type of hat with wings, in which the rear and front wings folded over the crown, and were kept in place by a ribbon and a button, this is why it is said to have three peaks or corners.  

Spanish Civil Guard troops march during the Spanish National Day military parade in Madrid. Photo: JAVIER SORIANO / AFP

Evolution of the tricornio

Both its shape and its size have changed considerably over the years to adapt to the needs of the civil guards – the main ones being that it is now a lot smaller and has also changed colour. Sometimes a gold band was added, while the more modern versions were plain black.

From felt hats, they changed to rubber to be able to withstand various weather conditions. The rubber version was based on a design created by the Civil Guard wives who decided on a new flap with buttons on each side. This version consisted of different layers and colors, but the shape has remained until today.

READ ALSO: Why does France give a gift of three cows to Spain every year? 

Later on, the rubber was covered in plastic, until it became replaced by vinyl, which would give it both shape and shine.

This again was subsequently changed to a material that resembled patent leather to promise better vision and durability.

In the post-war period, the uniform was modernised to prioritise combat requirements, practicality for transport units, and any symbols that may be required.

Starting in 1989, the tricornio came to be worn only as part of the gala uniform for ceremonies, parades and solemn acts, as well as in some operational services, such as those in charge of surveillance of embassies or airport security.  

Even so, these oddly-shaped hats have continued to be used throughout the 20th century and still serve as a visual reference and the most important symbol of the Civil Guard today.