PROWESS Four researchers have successfully deciphered a letter written in 1547 by Charles V to his French ambassador
Researchers have managed to decipher a letter from Charles V dating from 1547, consisting of of a series of "unintelligible" symbols. — AFP
They managed to solve a five-century-old riddle. Four researchers presented Wednesday at; Nancy their discovery, the deciphering of a letter written in its ambassador to France, shedding new light on relations between the kingdom ruled by then by Francis I, and the Holy Roman Empire.
To accomplish this “exceptional feat”, six months of work were spent. necessary to cryptographers from the Lorraine Computer Science Research Laboratory (Loria), associated with; a university historian of Picardy.
The letter, forgotten for centuries, was in the collections of the Stanislas library, at Nancy. C Pierrot, cryptographer at Loria, hears for the first time in 2019 about an “encrypted letter from Charles Quint” (1500-1558) by chance.
At the end of 2021 she sees for the first time the mysterious and incomprehensible letter bearing the signature of the King of Spain, addressed to its ambassador Jean de Saint-Mauris.
Cryptographers helped by a historian
C&écile Pierrot observes the letter for a long time, classifying “by distinct families” the approximately 120 symbols used by Charles V. She names them and decides to count their occurrences, to identify the combinations that could be repeated.
With two other researchers, she calls on IT to speed up research. The deciphering is done “small steps by small steps” by Charles V is diabolical.
In addition to its large number of symbols, “whole words are encrypted with a single symbol” and vowels preceded by a consonant are marked by diacritics, an inspiration probably coming from Arabic, explains C&écile Pierrot.
Degraded relations es between Charles V and François Ier
Another confusing element, the emperor uses “null symbols”, which mean nothing and in fact serve to mislead the adversary trying to decipher the message.
The click finally happened at the end of June: C&e;cile Pierrot and her team managed to isolate a sequence of words in the missive.
To do this, the three Nancy cryptographers called on Camille Desenclos, specialist at both cryptography and relations between France and the Holy Roman Empire in the 16th century.
Once deciphered, the letter “ comes to confirm the ” in 1547 relations between Francis I and the Emperor of the Holy Roman Empire Charles V, who nevertheless signed; a treaty of peace three years earlier.
Despite This peace, the two sovereigns maintain a “distrust” reciprocal “extremely strong” and seek “ s”weaken” each other.