Looking at the 24-foot-long Great Isaiah Scroll, the longest of 950 discovered Dead Sea scrolls, you'd assume it made someone's hand very, very tired. But the "near uniform" Hebrew script on the 2,000-year-old scroll discovered in 1946, which looks to the naked eye to have been written by one person, was likely written by two, according to a new study. Researchers at the University of Groningen's Qumran Institute employed "cutting edge" artificial intelligence to separate the ink from a digitized version of the scroll—which includes 66 chapters of the Hebrew Bible's Book of Isaiah across 54 columns divided into halves—then search individual characters for minuscule differences, per the Conversation. Focusing on the Hebrew letter aleph, which occurs more than 5,000 times, revealed changes in text after the 27th column, where two sheets of material are stitched together.
A change in writing utensil, writing fatigue, or some injury to the scribe might account for the shift. But the prevailing theory is that a second scribe, who "shows more variable writing patterns," took up the work of the first. "The ancient ink traces relate directly to a person's muscle movement and are person specific," reads the study published Wednesday in PLOS One, per the BBC. Researchers note there may have been "two different scribes working closely together and trying to keep the same style of writing." The differences in the aleph character were so subtle that the scribes may have come from the same school or family. It might even be "a father having taught a son to write," researchers guess. "Regardless of the exact explanation, our study demonstrates the ability to closely mirror another scribe's writing style, so much so that modern scholars" can be fooled. (Scroll fragments have just been found in a 60-year first.)