“If you look at the errors, you have a key to understanding math from a certain perspective. You can actually use al-Asiri’s errors to do proper calculations. That predictability and regularity is a cipher. It’s a key to understanding anything else that is based on the same code. We began applying it to other drawings in the Voynich manuscript. A predictable mathematical sequence is one of the most common replacement ciphers. We applied it to English and got nowhere. We tried French as it was spoken in the twelfth century, and nothing. The same thing with Arabic and Persian. Nothing. Then we thought about commonalities. Charles LaRoque and Ibrahim al-Asiri were diplomats as well as deeply religious men. They were creating an agreement designed to preserve their churches, correct? So, in what language would these men write that agreement? We thought they might have written it in Hebrew, the original language of the Old Testament, but LaRoque was a Christian and al-Asiri was a Muslim, and Hebrew was the language of the Jews. Both men would probably have had some anti-Jewish sentiments. The Bible was often translated into Greek and Aramaic. And Aramaic was the language of diplomacy throughout the Middle East for a thousand years, and virtually all Middle Eastern languages can be traced back to it; and the Aramaic alphabet was eventually adopted for writing the Hebrew language. Formerly, Hebrew had been written using an alphabet closer in form to that of Phoenician. Everything fit. We now know that Aramaic is the language used to write the Holy Agreement.”

Lilith seemed unable to speak, but she finally croaked out a question. “And the cipher?”

“We hit one last hitch. MindReader was able to translate the first page of the Book of Shadows, which is mostly introductions of Sir Guy LaRoque and Ibrahim al-Asiri and their various titles and political affiliations. Typical diplomatic stuff and not of any use to us because we know who they were.”

“Damn,” growled Violin, and a wave of disappointment began sweeping through the Mothers and Echo Team.

But Circe was not done. “The code is devious; it changes incrementally. MindReader’s pattern search figured this last part out. On the first page of the Book of Shadows, the mathematical error was exactly as described in the Codex. However, on the second page, the error is doubled, then tripled on the third page, and on and on until you get to page ten, then it resets to the first error. With that last piece, we can now calculate the rate of error and use those errors to create a key to crack the ciphertext.” She took a breath. “The Book of Shadows and the Voynich Manuscript are ours.”

“Good God,” murmured Church. “This is brilliant work, Circe.”

“Rudy and Bug did as much as I did,” she said.

“I will thank you personally when I see you,” he said. “Bug, how soon before MindReader deciphers both books?”