Level 1 — Absolute Beginner
Long ago, people wrote letters on clay. Some letters were put inside clay envelopes.
The envelopes were closed 4,000 years ago. No one could read the letters inside without breaking them.
Scientists built a special machine. It is called ENCI. The machine uses X-rays. X-rays can see inside the clay.
Now scientists can read the old letters. They do not have to break the envelopes. One letter was from a woman named Anna-anna to her husband.
- letter
- a written message sent to another person
- clay
- soft, wet earth that becomes hard when it dries
- envelope
- a cover that holds a letter inside
- machine
- a tool built to do a job
- X-ray
- a kind of light that can see inside solid things
- break
- to make something come apart
- husband
- the man a woman is married to
- old
- having existed for a long time
Level 2 — Elementary
Almost 4,000 years ago, merchants living in the ancient city of Kanesh, in what is now Turkey, wrote letters on small clay tablets. To keep the messages private, some tablets were sealed inside a second layer of clay, like an envelope.
For a long time, the only way to read a message hidden inside one of these clay envelopes was to break it open, which destroyed the beautiful seal designs pressed into the outer layer.
Now a team of scientists, led by expert Cecile Michel, has built a mobile X-ray scanner called ENCI. The machine can be taken apart, carried into a museum, and put back together to scan a sealed envelope in just a few minutes, creating a detailed 3D picture of the writing hidden inside.
Using ENCI at a museum in Ankara, Turkey, the team read a personal letter written by a woman named Anna-anna to her husband about money he owed. In another envelope, they even found a tiny, 4,000-year-old barley seed. The research was published in the journal npj Heritage Science.
- merchant
- a person who buys and sells goods for a living
- tablet
- a flat piece of clay or stone used for writing
- private
- meant to be kept secret from others
- seal
- a mark or design pressed into clay or wax to show ownership
- mobile
- able to be moved from place to place
- scan
- to examine something closely using a machine
- detailed
- having many small parts described clearly
- seed
- a small part of a plant that can grow into a new plant
Level 3 — Intermediate
Nearly four millennia ago, Assyrian merchants operating out of the trading colony of Kanesh, in what is today central Turkey, conducted business through an elaborate system of clay tablets, many of which were enclosed within an outer clay envelope bearing cylinder-seal impressions that authenticated the document and, in some cases, its sender.
Reading the text sealed inside one of these envelopes has traditionally required physically breaking it open, an irreversible act that destroys the miniature seal imagery on the surface, imagery that itself carries valuable art-historical and administrative information. A small number of envelopes were opened decades ago for exactly this purpose, at a permanent cost to the artifacts.
An interdisciplinary team led by Assyriologist Cecile Michel has now developed a mobile computed-tomography scanner, named ENCI, capable of being disassembled into components, transported to a museum collection, reassembled on-site, and used to scan a sealed envelope in a matter of minutes. The resulting three-dimensional model allows researchers to digitally separate the hidden tablet from its enclosing shell and read the cuneiform text without ever touching the physical seal.
Deployed at the Museum of Anatolian Civilizations in Ankara, the scanner recovered a personal letter from a woman named Anna-anna to her traveling husband concerning a debt owed in silver, along with the striking incidental discovery of a preserved barley seed inside a separate envelope documenting a loan. The findings, published in npj Heritage Science, mark the device's first full scientific presentation following earlier deployments at the Louvre.
- colony
- here, a settlement of merchants or settlers established away from their home territory
- cylinder seal
- a small engraved stone rolled onto clay to leave a repeating pictorial impression
- authenticate
- to prove that something is genuine or official
- irreversible
- not able to be undone or reversed
- interdisciplinary
- involving two or more different fields of study
- computed tomography
- an imaging technique that builds a 3D image from many X-ray cross-sections
- disassemble
- to take something apart into its separate pieces
- incidental
- happening as a minor accompaniment to something else
Level 4 — Advanced
The Old Assyrian merchant archives of Kanesh have long posed a peculiar epistemological problem for Assyriologists: several hundred letters and contracts remain sealed inside their original clay envelopes, their contents inaccessible without an act of physical destruction that irrevocably erases the very seal impressions that once authenticated them and that today carry independent art-historical value as miniature glyptic compositions.
That trade-off, between textual access and material preservation, has structured the field's relationship to these artifacts for a century, with only a small, deliberately limited subset of envelopes sacrificed to reveal their contents, leaving hundreds more effectively unreadable by conventional means.
The mobile scanner ENCI, developed by a team spanning Assyriology, X-ray physics, and computer science under Cecile Michel's direction, resolves this trade-off rather than merely mitigating it: engineered for disassembly into transportable components and reassembly within a host institution, the device performs computed tomography in situ, generating a volumetric dataset from which the enclosed tablet's cuneiform can be virtually extracted and read while the envelope itself, seal impressions intact, remains entirely undisturbed.
Deployment at the Museum of Anatolian Civilizations yielded results that illustrate the method's dual value, both documentary and material: a private letter from a woman, Anna-anna, negotiating a silver debt with her traveling husband's counterpart, recovered as legible cuneiform text, and, in an unrelated loan envelope, an intact four-millennium-old barley seed, a botanical trace that would have been irretrievably lost had the artifact been opened by conventional means. Published as the device's inaugural full scientific presentation in npj Heritage Science, following preliminary use at the Louvre, the work reframes non-destructive imaging not as a supplementary tool but as the discipline's necessary default for a corpus in which every physical intervention has historically been unrepeatable.
- epistemological
- relating to the nature, sources, or limits of knowledge
- irrevocably
- in a way that cannot be changed or reversed
- glyptic
- relating to carving or engraving, especially on gems or seals
- mitigate
- to make a problem less severe rather than eliminating it entirely
- in situ
- in its original place, without being moved
- volumetric
- relating to the measurement or representation of a three-dimensional volume
- documentary
- here, relating to the informational or record-keeping value of a source
- corpus
- a complete collection of texts or artifacts relating to a particular subject