  The Dead Sea Scrolls are tangible evidence of the Bible's ancient scribal
culture. Palaeography - the study of ancient handwriting - can provide access
to this scribal culture. However, one of the problems of traditional
palaeography is to determine writer identity when the writing style is near
uniform. This is exemplified by the Great Isaiah Scroll (1QIsaa). To this end,
we used pattern recognition and artificial intelligence techniques to innovate
the palaeography of the scrolls regarding writer identification and to pioneer
the microlevel of individual scribes to open access to the Bible's ancient
scribal culture. Although many scholars believe that 1QIsaa was written by one
scribe, we report new evidence for a breaking point in the series of columns in
this scroll. Without prior assumption of writer identity, based on point clouds
of the reduced-dimensionality feature-space, we found that columns from the
first and second halves of the manuscript ended up in two distinct zones of
such scatter plots, notably for a range of digital palaeography tools, each
addressing very different featural aspects of the script samples. In a
secondary, independent, analysis, now assuming writer difference and using yet
another independent feature method and several different types of statistical
testing, a switching point was found in the column series. A clear phase
transition is apparent around column 27. Given the statistically significant
differences between the two halves, a tertiary, post-hoc analysis was
performed. Demonstrating that two main scribes were responsible for the Great
Isaiah Scroll, this study sheds new light on the Bible's ancient scribal
culture by providing new, tangible evidence that ancient biblical texts were
not copied by a single scribe only but that multiple scribes could closely
collaborate on one particular manuscript.
