A few days ago, we talked about the solving of the penultimate Dead Sea Scroll and its code, achieved by researchers at the University of Haifa. Well, this time around, Spanish National Intelligence Center (CNI) has done their bit of sleuthing on unsolved historical affairs, by successfully cracking the 500-year-old secret code used by King Ferdinand II of Aragon (who was also the monarch of Sicily and later the co-ruler of Castile, responsible for the completion of the Reconquista of Spain). This late medieval coding system consisted of over 200 special characters that were preferred by the king for sending ‘hidden’ messages to his military commander, Gonzalo Fernández de Córdoba.
The code was found in the letters exchanged between Ferdinand and de Córdoba during the Italian Wars of the early 16th century that involved most of the major states of Western Europe including France, Spain, the Holy Roman Empire, and England. Unsurprisingly, as CNI specialists deciphered, much of the content of the letters was focused on orders, instructions, and troop deployments for military engagements. Interestingly enough, some of the letters had more than 20 pages of content, and a few of them even contained admonishing words for the commander for presumably dabbling in diplomatic initiatives before consulting with the monarch.

Portrait of Ferdinand II by Michael Sittow. Source: Wikimedia Commons
As for this code-cracking feat in question, the letters were originally displayed by the Army Museum in Toledo, in 2015. And they were undeciphered till then mainly because of the lost substitution table that was originally used by the king for his own decoding purposes. However, the CNI took matters into their hand, by borrowing two such letters, dating from 1502 AD and 1506 AD respectively. These documents corresponded to a key historical epoch when the French invaded the Spanish-controlled Naples, which lead to the showdown between the two Western European powers vying for the control of the Mediterranean region around Italy.
In any case, it took the CNI specialists over half-a-year to decipher the effective code, which had a total of 88 different symbols and 237 ‘combined letters’. Some experts have hypothesized that this ‘Great Captain code’ was the precursor to the ‘Vigenère cipher’, a technique of encrypting alphabetic text that reached its advanced state in the 17th century (and was noted as being unbreakable by Lewis Carrol). To that end, historians are looking forth to unravel the mysteries of most of these coded letters of Ferdinand II by utilizing the successful method of CNI.
Via: Independent