Why Did Anyone Write on Clay? A Medium That Survives Being Burned

A tablet is a lump of prepared clay shaped to fit the hand, written on while damp by pressing the corner of a cut reed into the surface, which produces a wedge-shaped impression rather than a drawn line, and that constraint shaped the script into combinations of wedges rather than curves. Tablets were then either left to dry, which is sufficient for a document nobody needs permanently, or deliberately baked, which makes them extremely durable. Damp clay can be smoothed and rewritten before drying. Important documents were sometimes enclosed in a clay envelope bearing a copy of the text and seal impressions, so that tampering with the inner tablet could be detected, which is a security arrangement with no modern equivalent in physical documents.

The survival pattern is unusual and explains what is known about these societies:

• •Unbaked tablets survive in dry conditions and dissolve in wet ones
• •Fire bakes unbaked tablets, so destroyed buildings preserve their archives better than intact ones
• •Several of the largest archives known survive because the building holding them burned down
• •Clay is worthless as material, so tablets were not recycled the way metal and parchment were
• •Tablets are small and robust, so they survive collapse and burial
• •The result is that hundreds of thousands are known and most have not been published

The overwhelming majority of tablets are administrative rather than literary, which is informative in itself. Receipts, ration lists, inventories, loan contracts, sale deeds, tax records, letters and legal judgements make up the bulk, produced by temple and palace institutions managing large quantities of grain, livestock, textiles and labour. Literary texts, including the well-known epics, hymns and wisdom literature, are a small fraction. School exercises are abundant, since training scribes involved copying standard texts repeatedly, and those exercises preserve works whose originals are lost. Mathematical and astronomical tablets record techniques of considerable sophistication. And the administrative material is what makes these societies among the best documented of the ancient world in economic terms, since nothing comparable survives from most later periods.

The script was not static across the three thousand years it was used, and the changes are traceable. It began around 3300 before the common era as pictures pressed or drawn into clay to record quantities of goods, developing from an earlier system of clay tokens sealed in containers. The pictures became progressively more abstract as scribes worked faster, and rotated ninety degrees at some point, so later signs bear little resemblance to what they depicted. Signs acquired sound values alongside meanings, which allowed the script to write names and grammatical elements and made it adaptable to unrelated languages, so the same system was used for Sumerian, Akkadian, Hittite, Elamite and others. The number of signs in use fell over time as the system was simplified, and it was finally displaced by alphabetic scripts.

Reading the script again required a specific piece of luck. A monumental inscription cut into a cliff face at Behistun in Persia recorded the same royal proclamation in three languages and scripts, one of which, Old Persian, was a relatively simple system that could be attacked because the names of known kings appeared in it. Henry Rawlinson copied the inscription at considerable physical risk in the 1830s and 1840s, and work by several scholars over subsequent decades used the Old Persian as a route into the Akkadian version. Confirmation came in 1857 when four scholars independently translated a previously unknown text and produced substantially matching results. Sumerian, a language unrelated to anything known, was reconstructed afterwards through bilingual material.

Pressing a cut reed into damp clay produces wedges rather than lines, which shaped the script, and baking makes tablets essentially permanent. Fire preserves archives, so several of the largest known survive because the building burned. Most tablets are administrative, which makes these societies unusually well documented economically compared with much later periods.