The team, led by Eren Şahiner of Ankara University’s Earth Sciences Application and Research Center, together with Tamer Koralay, Bilal Söğüt, Tunç Sezgin, and Yusuf Kağan Kadıoğlu, dated five specimens drawn from the Frigidarium’s fabric. Optically stimulated luminescence, or OSL, works by measuring the trapped charge accumulated in mineral grains such as quartz since they were last exposed to sunlight or heat. When a brick is fired or mortar quartz is exposed during preparation, its luminescence clock resets; from that moment, background ionizing radiation from the surrounding sediments, cosmic rays, and the sample’s own radioisotopes steadily winds the clock forward. In the laboratory, controlled optical stimulation releases the stored signal, and the intensity reveals the equivalent dose, the total radiation absorbed since the resetting event. Dividing that dose by the environmental dose rate yields an age.

What distinguishes this study is the rigor of its dose-rate protocol. The researchers documented every step, including grain-size-dependent attenuation of beta radiation, a carbonate water-equivalence correction specifically designed for lime-bound mortars, and an explicit assessment of gamma dose-rate heterogeneity. Lime mortars are notoriously difficult subjects for luminescence dating because their carbonate content alters the way water content and radiation attenuation interact, and the team applied the Carb-style modeling approach to handle this. Gamma dose-rate heterogeneity is a further subtlety: in a wall of compound masonry, where bricks and mortar alternate, the radiation field is not uniform, and a sample’s dose rate depends on the geometry of its immediate surroundings. Rather than treating this uncertainty as a nuisance to be ignored, the authors modeled the gamma-field geometry as a Bayesian nuisance parameter, propagating the dosimetric uncertainty of compound masonry directly into the final chronological posteriors.

The five OSL ages were then synthesized in a constrained Bayesian phase model, a framework adapted from the radiocarbon dating community, carrying only stratigraphic information and terminus post quem priors. In plain terms, the model was told only the relative order of events and the earliest possible dates, and then asked to reconcile the luminescence measurements into coherent phases of the building’s life. Three phases emerged. Primary construction of the Frigidarium falls in the late first to early second century CE, with a posterior median of 162 CE and a 95.4 percent highest-posterior-density interval spanning 60 to 323 CE. This is consistent with the flourishing of Roman bath architecture in Caria during the Antonine and Severan periods, when cities of western Anatolia competed to monumentalize their civic centers.

The second phase captures a repair episode, dated with a mode of 375 CE within an interval of 365 to 499 CE. The coincidence is striking: the great Eastern Mediterranean earthquake of 365 CE, generated near Crete and felt across the entire region, devastated coastal cities and is one of the most extensively documented seismic events of antiquity. The repair date aligns closely with that catastrophe, suggesting that the Frigidarium was damaged and subsequently restored in its aftermath. Archaeoseismology, the discipline that reads earthquake damage in ancient structures, has long catalogued tilted walls, displaced masonry blocks, and collapsed colonnades across the Mediterranean, but assigning absolute dates to such damage has remained difficult. Here, the luminescence clock provides an independent chronological anchor for a restoration that historical sources alone could never have pinned to this provincial city.

The third phase concerns the building’s terminal collapse. Under dosimetric priors alone, the model placed the collapse at a mode of 545 CE within a broad window of 405 to 802 CE, a range too wide to discriminate among the known seismic events of the period. The Eastern Mediterranean experienced what some scholars describe as seismic clustering between the fourth and sixth centuries, with major earthquakes in 494 CE and in 554 to 558 CE, as well as events around 610 to 630 CE. Any of these could, in principle, have delivered the fatal blow. The Bayesian model alone could not choose between them, and the authors were careful not to overstate what the luminescence data could resolve.

The decisive breakthrough came from archaeology rather than physics. Coins minted in 613 CE were found sealed beneath the collapse debris, providing a hard terminus post quem: the building could not have fallen before those coins were deposited. When this numismatic evidence was incorporated into the Bayesian model, the collapse window narrowed dramatically to 613 to 850 CE, with a mode of 633 CE. Within that refined window, the circa 610 to 630 CE seismic anchor dominates, achieving an overlap probability of 0.31 at a 25-year tolerance. The statistical conclusion is that a seismic trigger is the most probable cause of the terminal loss of the Frigidarium’s monumental function in the early seventh century CE, a period of chronic instability for the Eastern Roman Empire marked by Persian wars, plague, and persistent tectonic activity in western Anatolia.

Stratonikeia itself is an ideal laboratory for such work. Located in the Yatağan district of Muğla Province, the city has been the focus of long-running excavations directed from Pamukkale University, and previous studies have documented earthquake relics in the ancient city and at the nearby sanctuary of Hekate at Lagina. Earlier archaeometric investigations of Stratonikeia’s bricks, mortars, and building stones, including luminescence dating of bricks from the Erikli Basilica and characterization of the theater’s architectural stones, laid the groundwork for the present study. The Frigidarium, the cold room where bathers began or ended their circuit of the Roman baths, is a structurally massive space whose thick walls preserve a legible record of construction, repair, and destruction.

The methodological implications extend well beyond one building. Mortar dating by luminescence has matured over the past two decades, and reviews of the field have emphasized the need for transparent, reproducible dose-rate assessment, particularly for carbonate-rich materials. By publishing a fully documented protocol, treating gamma-field geometry as an explicit model parameter, and releasing the R and Python scripts implementing the dose-rate calculation, equivalent-dose modeling, and Bayesian phase chronology, together with full Monte Carlo posterior samples, the team has set a benchmark for how archaeoseismic chronologies should be constructed and reported. The approach converts scattered, imprecise age estimates into a coherent probabilistic narrative of a building’s biography.

For the wider public, the study offers something rare: a precise, quantified answer to the question of when a great Roman monument was born, when it was wounded, and when it died. The Frigidarium of Stratonikeia rose in the high empire, was patched after the great earthquake of 365 CE, and stood for roughly another two and a half centuries before an early seventh-century tremor ended its life as a functioning bath. In the layered ruins of Caria, the marriage of luminescence physics and Bayesian statistics is now capable of reading that biography directly from the walls themselves, giving voice to buildings that survived their own civilization by more than a millennium.

Subject of Research: Bayesian archaeoseismic chronology of the Stratonikeia Frigidarium using optically stimulated luminescence dating

Article Title: Bayesian archaeoseismic chronology of the Stratonikeia Frigidarium from construction to seismic collapse

Article References: Şahiner, E., Koralay, T., Söğüt, B., Sezgin, T., & Kadıoğlu, Y. K. (2026). Bayesian archaeoseismic chronology of the Stratonikeia Frigidarium from construction to seismic collapse. Archaeological and Anthropological Sciences, 18(10), Article 203. https://doi.org/10.1007/s12520-026-02564-9

Image Credits: AI Generated

DOI: 10.1007/s12520-026-02564-9

Keywords: luminescence dating, OSL, Stratonikeia, archaeoseismology, Bayesian modelling, Roman architecture, frigidarium, Roman baths, earthquake chronology, mortar dating, Anatolia, 365 CE earthquake

The award was formally conferred on June 27, 2026, during a ceremony held at the 50th Annual Conference of the Collegium Mediterranistarum in Tokyo. The milestone anniversary lent particular weight to the occasion, as the society marked half a century of promoting interdisciplinary research on the Mediterranean region while simultaneously honoring a new generation of scholars. The Herend Award, established in 1995 with the support of the Herend Porcelain Manufactory and its Japan sole distributor Hoshi Shoji Co., Ltd., is granted annually to promising young researchers for exceptional books and scholarly contributions concerning Mediterranean culture. Recipients traditionally receive an exquisite Herend porcelain decorative plate bearing the Gardens of the Mediterranean motif, inscribed with the winner’s name in gold, a fitting emblem for a prize that celebrates the intersection of European craft tradition and rigorous academic achievement.

The honored publication itself appeared under the imprint of the German Archaeological Institute, the Deutsches Archäologisches Institut, one of the most authoritative publishing venues for classical archaeology. Its subject, the ancient theatre at Messene, stands in the southwestern Peloponnese of Greece, where the ruins of the Hellenistic city founded in 369 BCE survive with unusual completeness. Unlike many ancient theatres whose superstructures have vanished almost entirely, Messene’s theatre retains substantial remains of its cavea, or seating structure, along with architectural fragments scattered across the site. This preservation allowed Yoshitake to undertake something rarely achievable for monuments of this class: a full architectural study that reconstructs the building’s design, construction history, and transformation across centuries of use.

At the heart of the monograph is a methodological commitment to meticulous documentation combined with detailed architectural reconstruction. Architectural studies of ancient theatres depend on the patient recording of every surviving block, seat, stairway, and fragment of masonry, followed by the analytical work of fitting those pieces into a coherent three-dimensional understanding of the original structure. By applying this approach to Messene, Yoshitake has produced the first comprehensive study of the theatre’s remarkably well-preserved ruins and architectural fragments. The volume traces the monumental evolution of Greek into Roman theatre architecture on the Greek mainland, a transition that has long fascinated historians of building technology because it encapsulates broader cultural and political shifts accompanying Roman expansion into the Hellenistic East.

One of the study’s most significant contributions lies in its analysis of the reuse of Hellenistic building materials. Ancient builders frequently recycled stone blocks, seats, and structural elements from earlier phases of a monument when renovating or rebuilding it, and these reused components preserve valuable evidence of earlier construction techniques and dimensions. By carefully distinguishing original Hellenistic fabric from later Roman interventions, the study is able to read the theatre at Messene as a layered document, one whose stones record successive generations of design decisions. This stratigraphic reading of architecture allows scholars to follow not only how the building looked at any given moment but also how engineering practices, aesthetic preferences, and civic priorities changed as Greek civic culture adapted to Roman rule.

Equally innovative is the monograph’s attention to ephemeral elements of ancient theatrical infrastructure that rarely survive in the archaeological record. Yoshitake’s study explores mobile wooden stages, temporary structures erected for performances that left little direct trace, and mechanisms derived from siege technology, devices whose engineering principles were transferred from military engineering to the staging of spectacles. These reconstructions address a persistent problem in theatre studies: the visible stone shell of an ancient theatre represents only part of the performance environment, while the machinery that enabled scene changes, special effects, and actor movement was often made of perishable materials. By reasoning from structural evidence, parallels, and engineering principles, the study sheds new light on ancient engineering and design practices that conventional excavation alone cannot recover.

The significance of this work extends beyond the boundaries of a single monument. Theatres were among the most complex buildings produced by ancient societies, requiring sophisticated understanding of geometry, acoustics, load-bearing structures, drainage, and audience circulation. Tracing how a Greek theatre of the Hellenistic period was modified under Roman influence illuminates the transfer of building technologies across the Mediterranean world and the ways in which local craftsmen and imperial authorities negotiated architectural change. The theatre at Messene, with its unusually complete remains, offers an exceptional case study for this process, and Yoshitake’s comprehensive treatment makes it newly available as a reference point for comparative studies of theatres throughout Greece, Asia Minor, and the wider Roman world.

The monograph also stands as a vital contribution to the understanding of ancient construction processes and urban evolution. Theatres did not exist in isolation; they anchored the civic life of the cities that built them, hosting festivals, political assemblies, and public spectacles that defined urban identity. Reconstructing the building history of the theatre at Messene therefore contributes to a broader picture of how the city developed, how its public spaces were maintained and transformed, and how investment in monumental architecture reflected the shifting fortunes of the community. Studies of this kind demonstrate that architecture, read carefully, can serve as a historical archive in its own right, complementing texts and inscriptions with material testimony.

For the Collegium Mediterranistarum, the awarding of the Herend Award to this volume reflects the society’s enduring mission of encouraging pioneering academic inquiry across Mediterranean studies. Founded to bring together Japanese researchers working on the many cultures of the Mediterranean basin, the Collegium has used the Herend Award since 1995 to spotlight scholarly work by early- and mid-career researchers whose contributions promise to shape their fields for decades. Yoshitake’s recognition underscores the increasingly international character of classical archaeology, in which a scholar based at a Japanese university can produce a definitive study of a Greek monument published by a German research institute and honored by a Japanese Mediterranean studies society, a network of collaboration that mirrors the ancient connectivity of the region itself.

The full monograph is available through the iDAI.publications catalog of the German Archaeological Institute, where readers can access the complete architectural documentation, reconstructions, and analysis that earned the work its distinction. As research on ancient theatres continues to evolve, incorporating digital surveying, three-dimensional modeling, and new perspectives on performance culture, The Theatre at Messene: An Architectural Study provides a foundational baseline of carefully verified observation against which future interpretations can be tested. The 2026 Herend Award affirms that such patient, technically rigorous architectural scholarship remains central to understanding the ancient Mediterranean, and it signals to the field that the theatre of Messene, long admired by visitors to the Peloponnese, has now received the comprehensive scholarly treatment its exceptional preservation deserves.

Subject of Research: Comprehensive architectural study of the ancient Greek theatre at Messene and its evolution from Hellenistic to Roman design

Article Title: Prestigious Herend Award bestowed upon comprehensive architectural study of the theatre at Messene

Article References: Prestigious Herend Award bestowed upon comprehensive architectural study of the theatre at Messene. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Herend Award, Messene, ancient theatre, archaeology, Greek architecture, Roman architecture, Hellenistic, Kumamoto University, German Archaeological Institute, Collegium Mediterranistarum, architectural reconstruction, Mediterranean studies