One of the first applications for any new technology is the Bible.  Gutenberg published a Bible around 1454 as what is thought to be the first major book printed using mass-produced movable type.  Movies about the Bible were produced as long ago as 1897. Publishers used a Univac computer to produce a concordance—a kind of index for all the words used—for a new Bible in 1955, which they said cut 23 years off the process.

Now, researchers are using image analysis and artificial intelligence (AI) to help determine when the first books of the Old Testament were written. They are using what some describe as the ancient equivalent of Post-Its.  And techniques developed through such handwriting analysis could end up being useful in identifying contributors to other older documents, even if it’s just through scribbled notes in the margin.

First, some history.  The first books of the Old Testament are the five books of Moses, also known as the Pentateuch, as well as the books of Deuteronomy to II Kings. It was traditionally thought that they were written after the Babylonian Exile of Israel in the 6^th century BCE, writes Isabel Kershner in the New York Times. In fact, it was thought that it might not be until around 200 BCE, when archeologists again start finding inscriptions, that there were enough literate people around to write down all the material, she adds.

However, that’s all predicated on the belief that the Old Testament couldn’t have been written any earlier than the Babylonian Exile because literacy rates were low—and this new research has demonstrated that that belief could be wrong.

The research worked like this. Applied mathematicians and archeologists got together to study messages scribbled on pieces of broken pottery, called ostraca, from the Kingdom of Judah (including and south of present-day Jerusalem) around 600 BCE. In the same way that one of us might grab a Post-It to jot down a note, military people in the Judahite army would grab an ostracon to write down an order to send to another person. While parchment was around, pottery was cheaper, especially for this sort of ephemeral note. And, particularly advantageous for the researchers, pottery lasts a long time.

First, researchers used image analysis to clarify the letters that the various people were writing, similar to the sorts of techniques researchers are using to more clearly identify letters in handwritten documents ranging from the Declaration of Independence to Einstein.

Next, they used AI to analyze the handwriting of the people writing the notes on the pottery. “The letters from pairs of texts were jumbled up and the algorithm separated them based on handwriting,” Kershner writes. “If the algorithm split the letters into two clear groups, the texts were counted as having been written by two authors. When the algorithm did not distinguish between the letters and left them together in one group, no position was taken; they may have been written by the same hand, or possibly by two people with similar styles.”

This study determined not only how many people might have written the notes, but, using the information in the notes, where they fit into the social hierarchy. “Based on a statistical analysis of the results, and taking into account the content of the texts that were chosen for the sample, the researchers concluded that at least six different hands had written the 18 missives at around the same time,” Kershner writes. “Even soldiers in the lower ranks of the Judahite army, it appears, could read and write.”

“The commander down to the lowest water master could all communicate in writing,” Arie Shaus, a mathematician at Tel Aviv University, tells Maddie Stone in Gizmodo. “This was an extremely surprising result.”

The notes were also written well, without spelling or grammatical errors. “There is something psychological beyond the statistics,” Prof. Israel Finkelstein of the Department of Archaeology and Ancient Near Eastern Civilizations at Tel Aviv University, one of the leaders of the project, tells Kershner. “There is an understanding of the power of literacy. And they wrote well, with hardly any mistakes.”

Obviously, if even the water boy is literate, there was a lot more literacy in that time period before the Babylonian Exile than just among scholars and priests.  What it means, then, is that the Old Testament could have been written hundreds of years before it was originally thought to be, the researchers say.

Ironically, the result makes the researchers’ original goal—determining who wrote the Old Testament—that much harder. After all, if even the water boy knew how to write, just about anyone could have made a first draft of what became what is arguably the most successful book in the history of the world.

“It would imply that it wasn’t just an elite class of teachers and scholars who could have created the books of the Bible,” writes Dan Seitz in Uproxx. “It could have been, quite literally, some dude hauling water who thought it was a good idea to write this religion stuff down.”

So next time you’re writing a Post-It note, be sure to write it carefully. You never know what conclusions future historians might be making of it.