Which plaintext languages to try?

[Jorge_Stolfi]

Hope the paleographers will respond.  My impression is that by around 1500 people in Europe still generally used Roman numerals, while in the 1600s many already used the "Arabic" (Westernized) numerals. At least literate people, like Barschius and Marci.

By the way, while browsing the Kircher letters, years ago, I saw one where some cardinal or bishop described to Kircher the binary number system...