Archives · Cryptography · History
From diplomatic letters to telegrams: recover the texts, understand their stakes and show how they can be read.
This journal opens with two letters from Marie de’ Medici to her ambassador in Rome. The images, proposed readings and uncertainties can be examined together.
First decipherment to our knowledge · 16 October 2026
Reading consolidated — 17 October 2026. Satoshi Tomokiyo confirms the key image and corroborates four numerical values across six occurrences. The continuous reading is retained; some characters remain probable but unconfirmed.
Madrid · Everett · Zea Bermúdez
Spain will never recognise its former colonies, Zea tells the United States minister. In cipher, Everett writes that he does not believe it: a language imposed by the rival party and by Russia. A passage cut from the 1826 printing, and eight pages never printed.
Read the dossier →Copenhagen · Griffenfeld · Louis XIV
In the spring of 1675 Denmark promises war to the allies at The Hague and secretly bargains over its neutrality with France: 600,000 écus, then 300,000 a year, an engagement handed to Terlon on 11 June and a Swedish marriage to please Louis XIV. Three months later the Scanian War begins.
Read the dossier →Afonso VI · Count of Vila Flor
“Even exposing yourself to the last extremity of a battle.” On 15 May 1663, the day after Don John of Austria invested Évora, Afonso VI ordered the Count of Vila Flor, in cipher, to risk everything to relieve the city. On 26 May, with Évora fallen, the order was repeated. On 8 June came Ameixial. Four ciphered letters, of 13, 15 and 26 May, are read in the record.
→ Read the recordDuplessis-Mornay · Tours
In 1824 the editors of Duplessis-Mornay's correspondence printed eight cipher passages from two letters of the summer of 1593 as they stood: they had no key. Two centuries later, the “folded” alphabet can be read. At Tours, while the League looks for a king and Henri IV abjures at Saint-Denis, the Protestant leader's correspondents put in cipher what they dare not write in clear: a decree planned to have the Duke of Guise quartered, packets stolen by the Duchess of Angoulême's people, the Count of Gramont in a plot in Béarn, the chancellor and Sourdis behind the truce — “le roy est trahi”, the king is betrayed. Starting hypothesis (“two letters per group”): Daniel Bourdeau (catalogue no. 371).
→ Read the recordCopenhagen · Just Høeg
January 1675: the Swedish army has just entered Brandenburg. In Copenhagen, Conrad Biermann, secretary of the German Chancery, copies every week the dispatches leaving for The Hague and Paris; their sensitive passages are in cipher. Thanks to an untitled key sheet in the “Chiffer” volume of the Rigsarkivet, they can be read again: Denmark watches, anxious, as the Elector of Brandenburg wavers — a few months before entering the war against Sweden itself (September 1675, the Scanian War). Thirty-seven letters, January–June 1675, to Høeg and to Meyercrone, read in full: the first published decipherment, to our knowledge.
→ Read the recordCharles XII · Bender
Bender, 26 April 1710. In exile among the Ottomans, Charles XII — reputed to be closed to any peace — writes in cipher that he is willing to negotiate with Denmark under Anglo-Dutch mediation, and gives the Council a “free hand” for an armistice, “even for a whole year”. Two enciphered copies, forgotten at Stade, read with a reconstructed key.
→ Read the recordFerducci · Fiume
Eight enciphered words in a letter otherwise in clear. On 19 July 1532, as Süleyman marched on Vienna, Ferdinand I's agent at Fiume offered to seize the French ambassador at sea on his way back from the sultan — most probably Antonio Rincon. A new reading of an unglossed letter, with a key drawn from contemporary decipherments and confirmed by an independent table of 1542.
→ Read the recordRome · Legate Filippo Sega
Twelve pages of continuous figures: excommunication, a third party, the Infanta’s claim against the Salic law, fear of Navarre’s “feigned conversion”. A probable and partial decipherment; earlier preliminary reading by Satoshi Tomokiyo (2019).
The context and the proposed reading →Marie de’ Medici · Savary de Brèves
Clear text, letters with different values and overlined numbers: the proposed reading concerns Savoy, political pressure and the limits of disarmament. The reading is consolidated; some characters remain probable.
The history and proposed passages →01 · The document
Facsimiles and archive references accompany the transcriptions. A graphical resemblance remains a decision to explain.
02 · The reading
The image, transcribed sign, proposed value and modernised text are separate. Contextual restorations remain visible.
03 · The evidence
A coherent sentence does not prove a key. Unresolved points, corrections and earlier work belong in the dossier.
Ciphered Europe