On its 105 yellowing pages, the only plain text is "Philipp 1866" on the flyleaf and "Copiales 3" at the end of the last page. "Philipp" is thought to have been an owner of the manuscript, while "Copiales" was used to give the secret writing its name: the Copiale Cipher.
To break the cipher, an international team of researchers tracked down the manuscript, now in a private collection, and transcribed a machine-readable version of the text.
The investigators began not even knowing the language of the encrypted document. At first they focused on the Roman and Greek characters sprinkled throughout the Copiale Cipher, isolating them from the abstract symbols and attacked it as the real text.
"It took quite a long time and resulted in complete failure," Knight said.
After trying 80 languages, the cryptography team realized the Roman characters were "nulls" intended to mislead readers, somewhat like how pig Latin adds the suffix "ay" to words in an attempt to confuse listeners. It was the abstract symbols that held the message.
"It was exciting to decode," Knight recalled.
One idea that eventually bore fruit was that abstract symbols with similar shapes in the Copiale Cipher represented the same letter or groups of letters — for instance, the symbols with the circumflex "^" over them were actually the letter "E." The researchers also detected an extraordinarily common three-symbol cluster, which they deduced represented the letters "cht," a common trio in German. Eventually from these lines of attack, the first meaningful words of German emerged: "Ceremonies of Initiation," followed by "Secret Section," as translated.