The new study, published on Monday in the Proceedings of the National Academy of Sciences, combined archaeology, Jewish history and applied mathematics, and involved computerized image processing and the development of an algorithm to distinguish between the various authors issuing the commands.

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. Even soldiers in the lower ranks of the Judahite army, it appears, could read and write.

“There is something psychological beyond the statistics,” said Prof. Israel Finkelstein of the Department of Archaeology and Ancient Near Eastern Civilizations at Tel Aviv University, one of the leaders of the project. “There is an understanding of the power of literacy. And they wrote well, with hardly any mistakes.”

The study was based on a trove of about 100 letters inscribed in ink on pieces of pottery, known as ostracons, that were unearthed near the Dead Sea in an excavation of the Arad fort decades ago and dated from about 600 B.C. That was shortly before Nebuchadnezzar’s destruction of Jerusalem and the kingdom of Judah, and the exile of its elite to Babylon — and before many scholars believe the major part of the biblical texts, including the five books of Moses, also known as the Pentateuch, were written down in any cohesive form.

The Arad citadel was small, far-flung and on an active front, close to the border with the rival kingdom of Edom. The fort itself was only about half an acre in size, and probably would have accommodated about 30 soldiers. The wealth of texts found there, recording troop movements, provisions and other daily activities, were created within a short time, making them a valuable sample for looking at how many different hands wrote them.