Ancient Kidney Stone Reveals Hidden Infection in a Bronze Age Man

Buried beneath a kurgan in the North Caucasus some 5,300 years ago, a mature man carried with him a small, silent record of suffering: a calcified stone that formed somewhere within his urinary tract. Researchers led by Natalia Berezina of Lomonosov Moscow State University, together with Julia Gresky of the German Archaeological Institute, have now subjected that stone to one of the most thorough analytical workups ever applied to an ancient biological concretion. Their study, published in Archaeological and Anthropological Sciences, identifies the object as a urolith of infectious origin, making it direct physical evidence of chronic urogenital disease in the Early Bronze Age. The finding is remarkable not because stones are rare in modern clinics, but because they almost never survive in the archaeological record, and because the mineral chemistry locked inside them can still speak across five millennia.

The specimen came from the Ipatovo-5 site in the Stavropol region of Russia, associated with the so-called Steppe Maikop horizon of the final third of the fourth millennium BCE, roughly 3300 to 3000 BCE. The burial contained the remains of a man aged 40 to 49 years at death, an estimate based on standard skeletal aging methods such as assessment of the pubic symphysis. During excavation, archaeologists recovered a small calcified object whose identity was not immediately obvious. Concretions found in burials can be urinary or gallbladder stones, but they can also be soil nodules, mineralized plant material, or other pseudopathological formations. Distinguishing a genuine biological stone from a geological look-alike requires chemistry, and that is precisely what the team set out to deliver.

The analytical protocol was unusually broad. The researchers employed Fourier transform infrared spectroscopy with attenuated total reflectance to identify molecular bonds and mineral phases, X-ray diffraction to resolve crystal structures, micro-X-ray fluorescence mapping to chart elemental distributions across the stone, scanning electron microscopy to image its microstructure, combustion-based elemental analysis to quantify carbon, hydrogen, nitrogen, sulfur and oxygen, and both tabletop micro-computed tomography and photon-counting computed tomography to reveal internal architecture in three dimensions. Each technique answers a different question, and together they converge on a diagnosis in a way no single method could. This kind of multi-method strategy mirrors the morpho-constitutional analysis that clinical urologists use today, in which a stone’s composition and structure are read as a biography of the conditions that formed it.

The mineralogical verdict was unambiguous. The stone’s matrix consists of carbapatite, the carbonate-rich form of calcium phosphate also known as carbonate apatite, together with hydroxyapatite and whitlockite, a magnesium-bearing calcium phosphate. That particular assemblage is a clinical hallmark of infection-driven stone disease. Certain bacteria, most famously urease-producing species such as Proteus and related organisms, split urea in urine into ammonia, driving the local pH upward. In alkaline urine, calcium phosphate phases precipitate readily and can grow into substantial stones. In modern urology, a phosphate-dominant stone of this kind points the clinician straight toward chronic urinary tract infection as the underlying cause, and the same logic applies retroactively to the archaeological specimen.

Just as telling is what the stone does not contain. The complete absence of calcium oxalate and uric acid, the two mineral phases that dominate metabolic and dietary-related stone disease, rules out diet as the primary lithogenic factor. Many popular accounts assume ancient stones must reflect rich or unbalanced diets, and indeed some archaeological cases have been interpreted that way. Here, the chemistry says otherwise. The Ipatovo man’s stone formed in a urinary environment altered by bacterial infection, not by the excess of oxalate-rich plants, purines, or other dietary components that produce oxalate and uric acid calculi. This distinction matters for how archaeologists reconstruct ancient lifeways: a stone’s composition is a physiological document, and misreading its mineralogy can lead to unfounded claims about ancient cuisine.

The data leave one genuine ambiguity, and the authors are careful not to overclaim. Two anatomical origins fit the evidence equally well. The stone could be a renal calculus, formed in the kidney as a consequence of an upper urinary tract infection such as chronic pyelonephritis. Alternatively, it could be a prostatic calculus, formed in situ within the prostate gland as a result of chronic bacterial prostatitis, a condition in which tiny infection-driven phosphate stones can accrete around ductal debris. Prostatic stones have a specific chemistry tied to infection and often preserve bacterial imprints, as clinical research has shown. Without precise contextual information about the stone’s position within the pelvis, which burial environments rarely preserve, the team cannot definitively choose between the two scenarios. Either diagnosis, however, points to the same underlying reality: a chronic, infection-associated urogenital condition.

What would that have meant for the man while he lived? Chronic pyelonephritis and chronic bacterial prostatitis are both debilitating conditions. Renal infection can produce recurring fever, flank pain, and progressive scarring of kidney tissue, while chronic prostatitis causes persistent pelvic pain, difficult and painful urination, and, when stones obstruct the urinary tract, potentially serious complications. A stone lodged in the ureter or bladder can cause colic of legendary severity, hematuria, and secondary infections. In a world without antibiotics, surgical stone removal, or even effective analgesia beyond herbal preparations, such a condition would have significantly degraded the man’s quality of life, likely for years. The stone is thus not merely a curiosity; it is a durable trace of prolonged illness in a person who otherwise left no written record and whose skeleton may show few or no overt signs of the disease.

The case also fills a conspicuous gap in the paleopathological literature. Urolithiasis, the medical term for urinary stone disease, is exceedingly common today, affecting roughly one in ten people in industrialized countries, yet confirmed archaeological cases remain scarce. Reported examples include an approximately 8,500-year-old bladder stone from Uzzo Cave in Sicily analyzed by infrared spectroscopy, a bladder stone from a Neolithic passage grave at Chenon in France, prostatic stones in Late Pleistocene and Early Holocene burials at Al Khiday in central Sudan, stones from medieval cemeteries in Poland and Catalonia, a giant bladder stone in the mummy of a nineteenth-century Lebanese Maronite Patriarch, and a kidney stone in a nineteenth-century skeleton from Peoria, Illinois. Each new well-analyzed specimen adds a data point to a map of ancient disease that is still mostly blank, particularly for prehistoric pastoral societies of the Eurasian steppe.

The Ipatovo man lived during a transformative period in the region. The Maikop phenomenon of the North Caucasus is known for its rich kurgan burials, metalwork, and connections stretching across the steppe and toward the Near East. Recent research on Bronze Age communities in the Caucasus and the southern Russian steppes has documented the emergence and intensification of dairying, reconstructed diets from stable isotopes, and charted ancient genomes across a 3,000-year interval. Against that backdrop, a case of chronic infectious urolithiasis offers a ground-level view of health that population-level studies cannot provide. It reminds researchers that the people behind the isotopic ratios and genetic profiles carried burdens of chronic disease whose prevalence in prehistory remains essentially unknown.

Methodologically, the study also showcases how modern clinical imaging and spectroscopy can be transplanted into bioarchaeology. Photon-counting computed tomography, a cutting-edge hospital technology that separates materials by their X-ray attenuation signatures, and micro-CT, the standard for three-dimensional stone analysis in urological research, both revealed the internal structure of the specimen non-destructively. The work was supported by the Russian Science Foundation and carried out with the shared research facilities of Moscow State University. For the authors, the Ipatovo urolith demonstrates the power of an integrated analytical approach in bioarchaeology: a single small stone, interrogated with enough techniques, can yield a diagnosis, an etiology, and a window onto the lived experience of illness in a world that vanished more than five thousand years ago.

Subject of Research: Paleopathological analysis of an infectious-origin urinary stone from an Early Bronze Age burial in the North Caucasus

Article Title: Urolithiasis in the early bronze age of the North Caucasus: a paleopathological case study and insights into ancient lifeways

Article References: Berezina, N. Y., Statkus, M. A., Kalmykov, A. A., Abdrashitova, I. V., Kolesnik, I. V., Platonov, V. B., Shashurin, D. A., Garmay, A. V., Korobkova, V. V., Ryleeva, V. S., & Gresky, J. (2026). Urolithiasis in the early bronze age of the North Caucasus: a paleopathological case study and insights into ancient lifeways. Archaeological and Anthropological Sciences, 18(10), Article 209. https://doi.org/10.1007/s12520-026-02574-7

Image Credits: AI Generated

DOI: 10.1007/s12520-026-02574-7

Keywords: urolithiasis, paleopathology, Early Bronze Age, North Caucasus, Maikop culture, carbapatite, infectious disease, micro-CT, FTIR spectroscopy, bioarchaeology, Ipatovo-5, urinary tract infection