Room L.1932 and the entrance to the upper room L.1238 in the background, view from the SW, 2022 season. Credit: M. Jean et al. 2026

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by Guillermo Carvajal

May 6, 2026

The results of a study show that scribes did not always refine their clay, barely used fire to harden the texts, and that tablets made in the workshop coexisted with others brought from outside.

An international team of archaeologists and scientists has shed light on how the famous cuneiform writing tablets were manufactured in ancient Assyria. The study, published in the journal Archaeometry, focuses on an exceptional discovery made between 2019 and 2023 in the city of Nineveh, present-day Iraq, by the Iraqi-Italian archaeological expedition.

There, inside an elite residence, a room was discovered containing more than 200 broken tablets, a large block of raw clay (one meter high, 1.9 wide, and 1.6 long), and what could be a tiny bronze stylus. The context, dated just before the fall of Nineveh in 612 BCE, has been interpreted as a possible scriptorium or tablet-making workshop.

The research, led by Mathilde Jean (University of Paris Nanterre and the British Museum), analyzed in depth five of those tablets and the clay clod to answer three fundamental questions: whether all the tablets could have been made in that same workshop, which techniques the scribes used, and how to better interpret this archaeological space. The results, far from showing uniformity, reveal a surprising diversity of procedures and materials.

A Mansion with Bitumen Benches

The building where the samples were found is a large terraced house, a high-ranking residence or a small palace, located near the Gate of Adad, in the northeast of the city. The key room, called L.1238, contained clay benches coated with a thin layer of bitumen (a type of natural waterproof tar).

In the adjoining room, L.1932, connected by a wide doorway, is where most of the tablets, the large clay block, and the possible stylus appeared. The texts on the tablets are almost all academic in content: word lists, divinatory, medical, magical, literary texts, and dynastic chronicles. Some are written in Assyrian script and others in Babylonian script, already pointing to a possible mix of origins.

The tablets, when found, were already fragmented, crushed, and with their surfaces badly damaged by water and fire. In fact, the fact that they suffered the effects of a great fire—the one that accompanied the conquest of the city—is one of the keys that researchers have used to study whether the tablets were intentionally fired in antiquity.

Microscopes and Rays to Read the Clay

To reveal the composition and treatment of the clays, scientists used two main techniques. On one hand, petrography, which consists of observing thin slices of the samples under a polarized light microscope to identify minerals and inclusions (sand grains, tiny shells, plant remains).

On the other hand, they used a scanning electron microscope with X-ray spectroscopy (SEM-EDX), which allows for knowing the exact chemical composition of the clays and seeing their microstructure in great detail.

The chemical analysis showed that all the analyzed clays are highly calcareous, meaning they have a calcium oxide content above 15% (in fact, it ranged between 19.5% and 24.1% in most cases). This composition is compatible with the alluvial deposits of the Tigris River, which flowed near Nineveh, although the researchers point out that more geological samples from the area would be needed to pinpoint the exact origin.

Four Types of Clay, Four Ways of Working

What was truly revealing was the variety of clay preparation techniques. The researchers classified the samples into two large petrographic groups and two independent samples (unique in their composition).

Unprocessed or minimally kneaded clay tablets: Two of the tablets (NE.21.O.521 and NE.21.O.654) were made of calcareous clay containing abundant inclusions (calcareous and siliceous minerals, and some microfossils). The uneven distribution of these grains and the high porosity indicate that the clay was barely kneaded and not refined. It was simply taken as-is from a natural deposit. In these cases, the texts were written in Assyrian script and contained very rare works, such as a copy of the text “Aa II” and a Dynastic Chronicle, which were previously known only from a single manuscript in the famous Library of Ashurbanipal.

Highly refined (levigated) clays: The clay clod (NE.22.S.357) and one of the tablets (NE.21.O.671) presented an almost identical composition, both chemically and mineralogically. This is strong evidence that this specific tablet was made directly from clay taken from that block. Both samples were very fine, with few inclusions, indicating that the clay had undergone a levigation process (settling to remove coarse particles). However, despite this refinement, they also showed high porosity and little kneading. That is, the clay had been refined but not worked enough to remove air bubbles. The content of this tablet was illegible.

A tablet with coarse inclusions: Sample NE.21.O.540, a text of omens written in Babylonian script, was also made of unprocessed clay, but with very coarse calcareous inclusions. Its chemical composition was different from the others, with the highest values of magnesia and iron oxide. The researchers believe this tablet could not have been made with the same local clay as the others, or it came from another part of Assyria or was copied from a Babylonian original with different clay.

An organic and different tablet: Sample NE.21.O.542 was the strangest of all. Its clay was dark, rich in organic matter, and contained plant remains, wood, and even bones. Chemically, it had the highest calcium (30.9%) and the lowest values of magnesia, alumina, and iron. This tablet, whose text is illegible due to poor preservation, must have come from a completely different place and perhaps was made by a scribe with a different technical tradition.

The Surprise of Unfired Clay

One of the most significant findings for the history of cuneiform writing is that none of the analyzed tablets had been intentionally fired. The electron microscope images showed that the clays were either unfired or minimally fired, with a compact microstructure or an initial vitrification of clay filaments, but they never reached the high temperatures of a kiln. This contradicts the old belief that library tablets were deliberately fired to preserve them.

The article explains that the famous fire of the Library of Ashurbanipal during the fall of Nineveh caused fire damage to many tablets, and that in the 19th and 20th centuries, excavators and museums themselves often fired the tablets to harden them, without always recording it. But in this case, being a modern and controlled excavation, scientists can state with certainty that these tablets were never fired in antiquity.

In fact, the poor state of preservation and the visible deformations in the group of tablets are consistent with accidental fire exposure during the city’s destruction, not with deliberate firing.

A Tablet Workshop or a Storage Room?

The almost identical composition between the clay clod and tablet NE.21.O.671 proves that at least one of the tablets was made right there. As the authors write: The almost identical composition of clay clod NE.22.S.357 and tablet NE.21.O.671, found in the same context, suggests that the clay clod effectively served as a supply of clay for tablets, at least in the case of NE.21.O.671, but presumably also for other tablets found in that context that were not analyzed in this study.

However, the diversity of clays found proves that not all the tablets were made there. The owner of this mansion created a collection by mixing in-house production with external acquisitions, especially tablets written in Babylonian script (of which 92 have been identified in the total set).

In addition, an interesting question arises: what were the bitumen-covered benches in the adjoining room for? The researchers rule out their use for levigation (clay refinement), because that task requires a basin or deep container, not a flat surface.

The most plausible hypothesis is that these benches served as a work table for shaping the tablets (stretching, rolling, or folding the clay) or perhaps for storing finished but still raw tablets, protecting them from moisture with the bitumen. The tablets appeared piled up in front of the adjoining room’s doorway, which may indicate that they were thrown there and abandoned by enemy soldiers after the conquest of the city in August 612 BCE.

Scribes Who Did Not Always Refine Their Material

The study also offers a new perspective on the relationship of scribes with their own work material. Traditionally, it was thought that these highly educated literates, who copied rare and complex works, carefully refined and kneaded their clay to avoid impurities or air bubbles interfering with the writing. But the results show the opposite: most of the clays were unprocessed or only partially processed, and porosity was high.

The researchers conclude that, since the tablets were not going to be fired, the heterogeneity of the clay was not a serious problem. Unlike pottery, where vessels must withstand high temperatures and be made thin, a raw clay tablet can be written on perfectly well, even if it has coarse grains or small voids.

This suggests that scribes were not specialists in clay preparation; they probably obtained the material already levigated from potters’ workshops or extracted it themselves and then gave it only minimal kneading, if any. As the authors point out: The commonly accepted assumption that scribes would have routinely levigated and worked their clays (to prevent inclusions and voids from interfering with the writing process) therefore needs to be revised.

In short, the research opens a window into the everyday reality of written production in the Neo-Assyrian Empire. It shows that, beyond the idealized image of the great Royal Library of Ashurbanipal, there were small workshops in elite residences where tablets were produced, stored, and collected in a heterogeneous manner, with different origins and varying levels of technical refinement.

And it reveals that the clay with which the history of Mesopotamia was written was often a much coarser and less prepared material than previously believed.

SOURCES

Jean, M., M.Spataro, J.Taylor, et al. 2026. A Newly Discovered Tablet-Making Facility in Nineveh: Insights From Scientific Analysis. Archaeometry1–12. doi.org/10.1111/arcm.70144

Topographic map of Nineveh with the excavation areas of the Iraqi–Italian Archaeological Expedition. Credit: M. Jean et al. 2026

Part of the tablets found in room L.1932 during their excavation. Credit: M. Jean et al. 2026