An ancient recipe revealed
At the Fayaz-Tepe Buddhist monastery, a complex of sun-baked ruins near Termez, Uzbekistan, scientists have uncovered the molecular recipe for the site's Greco-Buddhist sculptures. This monastery, active from the 1st to 3rd centuries CE, was an important Buddhist center on the Silk Road under the Kushan Empire. The art here has a distinct blend of Hellenistic and Indian styles, visible in the features of the clay and gypsum figures that once adorned the walls.
Analysis of the organic materials used to bind these unbaked clay sculptures showed a substance unique to this ancient workshop. Using proteomic and genomic analysis, researchers identified a specific two-part mixture: rabbit collagen, and camel milk. This combination of animal glue made from rabbit and a casein binder from camel milk has not been documented in artistic traditions elsewhere. The use of binders like animal glue, milk, and eggs was common in the ancient world to give plasticity to modeling materials and ensure pigments adhered to surfaces. However, the choice of rabbit and camel points to a highly localized practice, relying on the specific fauna of the Bactrian region.
Decoding the molecular evidence
Scientists used a technique called shotgun proteomics to identify the proteins in microscopic samples from the sculptures. This method breaks down all proteins present into smaller fragments called peptides. The mass of these peptides is then measured with extreme precision and compared against vast databases of known protein sequences. The analysis identified peptides matching collagen from the family Leporidae (which includes rabbits and hares) and casein proteins specific to the genus Camelus.
The presence of camel milk was an unexpected discovery. While bovine milk (from cows) was a known binder in other ancient cultures, camel milk was not a common artistic material. This finding shows that the artisans of Fayaz-Tepe were resourceful, using readily available local animals. The Bactrian camel, native to Central Asia, was a part of life on the Silk Road. The rabbit glue, or animal collagen, would have provided strong adhesion for the clay and pigment layers, ensuring the durability of the artwork. This molecular evidence records the material science and workshop traditions of a culture that existed nearly two thousand years ago. The sculptures that remain are now primarily housed in history museums in Termez and Tashkent for their preservation.