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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13 changes you may have missed about Spain’s new ‘Civil War’ law

Spain's Democratic Memory Law is the Spanish government's attempt to deal with the complicated historical legacies of its Civil War. Here are 13 takeaways you might have missed from the controversial legislation.

13 changes you may have missed about Spain’s new ‘Civil War’ law

Spain’s new Democratic Memory Law, sometimes called the Historical Memory Law, passed the Spanish Senate on October 5th 2022 and officially became law a few weeks later, on October 21st.

It is a piece of wide-ranging but controversial legislation that aims to settle Spanish democracy’s debt to its past and deal with the complicated legacies of its Civil War and the dictatorship of Francisco Franco, which lasted from 1939 to 1975.

Legislation concerning Spain’s dictatorial past is always controversial, and this law was no different – it passed the Spanish Senate with 128 votes in favour, 113 against, and 18 abstentions.

The Spanish right has long been opposed to any kind of historical memory legislation, claiming that it digs up old rivalries and causes political tension. Spain’s centre-right party, the PP, have promised to overturn the law if it wins the next general election.

READ ALSO: Spain’s lawmakers pass bill honouring Franco-era victims

But what does the law actually say?

And what does it do?

The Local has broken down thirteen of the key takeaways you might have missed.

  • Convictions – The law declares Francoist courts illegal, therefore annulling convictions made by them or any affiliated criminal or administrative bodies since 1936. According to the official bill (BOE), which you can find here, Article 5 deals with “the illegality and illegitimacy of the courts, juries and any other criminal or administrative bodies that, since the Coup d’état of 1936, imposed, for political, ideological, religious conscience or belief, convictions or sanctions of a personal nature”. 
  • Locating victims – The Spanish government will lead the search for the thousands of missing persons left over from the Civil War and disappearances during the dictatorship. A map of potential mass grave sites will be created and according to Article 16 of the law, “annual exhumation data will be made public… which will include the number of registered petitions, the number of graves and remains of people located.” Article 17 outlines plans for an ‘integrated map’ to help locate victims and burial sites, which will cover the whole of Spain.

    Remains in the bottom of a mass grave at the San Roque cemetery in Puerto Real near Cádiz. Photo: CRISTINA QUICLER/AFP
  • DNA bank – To aid in this search, a state-run DNA bank will be created to help the descendants of missing victims better compare genetic profiles during the identification of the remains. Article 23 of the law describes this as a “state-owned DNA database, attached to the Ministry of Justice, which will have the function of receiving and storing DNA profiles of victims of the Civil War and the dictatorship and their families, as well as people affected by the abduction of newborns”. 
  • Census – A ‘National Census of Victims of the Civil War and the Dictatorship’ will also be created in order to try and piece together the often fragmented information available about those who died during the Civil War, and countless victims of ‘forced disappearances’ during the dictatorship. 
  • Victimhood – The law also redefines the definition of what a victim is, extending it to someone who suffered physical, moral or psychological harm, property damage, or any infringement of their fundamental rights at the hands of Francoism. The dates for this new definition are from the date of the initial coup d’état on July 18th, 1936, all the way up until the creation of the 1978 Constitution. 
  • Days of Remembrance: Two days to remember: the law sets aside October 31st as a day of tribute to all the victims of the military coup, the Civil War and the dictatorship, whereas May 8th will be used as a day of memory for all the men, women and children exiled due to the dictatorship.
  • The Valley of the Fallen – The controversial Valley of the Fallen (Valle de los Caídos), where Franco was buried but has since been exhumed and moved, is to be renamed Valle de Cuelgamuros and the mausoleum repurposed. 

    READ ALSO: Spain to relocate remains of Franco’s fascist allies to more low-key grave

  • Human rights violations: a specialised prosecutor will investigate violations of international law and human rights that occurred during the Francoist period. Article 28 outlines the role of a prosecutor “created to investigate acts that constitute violations of international human rights law… including those that took place during the coup d’état, Civil War and the Dictatorship”. 
  • Francoist symbolism: Symbols, shields, insignia, plaques and any other symbolism glorifying Franco or Francoism, including objects attached to public buildings or displayed on public roads, will be removed. It also introduces measures to deal with the revocation of distinctions, appointments, titles and other institutional honours, including decorations and rewards or noble titles, which were bestowed during the dictatorship.
  • Groups banned – Equally, any foundations and associations considered Franco-apologist, or that glorify and engage in the direct or indirect incitement of hatred or violence against the victims of the Civil War and dictatorship, will be banned.
  • Education -The legislation also makes an attempt to better educate young Spaniards about the historical legacies of Francoism. The curriculum of ESO, FP and Baccalaureate courses will be updated to highlight “the repression that occurred during the war and the dictatorship”. 
  • International Brigade – Descendants of soldiers who fought in the International Brigades on the side of the Republicans will be eligible for fast-track Spanish citizenship as a result of the legislation, and they won’t have to give up their other nationality in order to do so.

    READ ALSO: Descendants of International Brigades can get fast-track Spanish nationality

    The fighters themselves have been able to apply for Spanish citizenship since 1996, though they were required to drop their other nationality. Spain’s 2007 Historical Memory Law removed that requirement, though the offer of citizenship was not extended to their descendants. According to the Asociación de Amigos de las Brigadas Internacionales (AABI), a group involved with drafts of the legislation, there are at least one hundred known descendants that could benefit from the symbolic citizenship offer.

  • Ley de Nietos – Known as the Grandchildren’s Law in English, the law also allows for descendants of Spaniards who fled Spain during the Civil War and Franco’s dictatorship to claim Spanish citizenship without ever having lived there. According to estimates, as many as 700,000 people, the majority in Latin America, could be eligible. It is even believed that Latino migrants living in Spain illegally could be eligible for citizenship. Between the end of the Civil War in 1939, and 1978, when Spain’s new constitution was approved as part of its transition to democracy, an estimated two million Spaniards fled the Franco regime.
    READ ALSO: Spain’s new ‘grandchildren’ citizenship law: What you need to know