People in Motion: Tracing Human Mobility across the Mediterranean in the Byzantine Era

People in Motion was a three-year project funded by the Cypriot Research and Innovation Foundation in the context of the Excellence hubs call (EXCELLENCE/1216/0023). Its aim was to explore human mobility across the Mediterranean during the Byzantine period, thus covering a geographic area the connectivity of which has been highlighted by numerous scholars during a key period of interaction and societal transformation. Human mobility has played a key role in the formation of the multi-ethic Byzantine state and People in Motion was the first project to systematically explore this phenomenon based on the most direct evidence of the individuals in motion, their skeletal remains. To this end, the project focused on material from Tunisia, Morocco, Italy, Greece and Cyprus and it has been materialised in close collaboration with colleagues from the Cypriot Department of Antiquities, University College London, Ephorate of Antiquities of Messene, Ephorate of Antiquities at Rethymno, University of York, and University of Cape Town. Human mobility was explored using a combination of macroscopic (dental morphology), microanalytical (dental calculus microdebris analysis of indigenous and imported plant species and minerals), and biochemical (strontium isotope analysis) methods.

Map showing the location of published strontium isotopic values in the Mediterranean

Data collection involved the dentition of 201 individuals from ancient Messene, Agios Nikolaos Mavromati, Eleftherna (Greece), and St George’s Hill (Cyprus) and 100 individual teeth from Sicily. In these cases, the skeletal assemblages had been studied by other colleagues in the past, hence data collection was restricted to dental markers of mobility (nonmetric traits, dental calculus inclusions, strontium isotopes). For Bulla Regia (Tunisia), Volubilis (Morocco), Agios Vasileios Pelekanadas and Christianoi (Greece), and Amathus (Cyprus) no prior skeletal study had been conducted, thus macroscopic data collection in these assemblages extended beyond the strict scope of mobility and encompassed the broader osteobiography of these individuals, that is, demographic characteristics, markers of occupation, health and disease, and metric analysis. The total sample on which a full osteobiographic study was performed amounted to 411 skeletons.

The results of the project have supported mostly regional mobility in Byzantine Nicosia, Cyprus, and Late Antique Bulla Regia, Tunisia, with few individuals originating in faraway locations in both cases. Data from Greece and Sicily is currently under analysis but overall supports the pattern seen in Tunisia and Cyprus. These results are very important in challenging the notion of major migrations as the key expression of movement in the Byzantine Empire. In exploring human mobility, People in Motion has also made important methodological contributions to the bioarchaeological study of mobility. Our team has refined existing methods for biodistance analysis, and engaged in a successful experimental study that showed that burning plants in an open fire is an effective method to export modern plant material for establishing a bioavailable strontium isotopic baseline. Using this method, we have now mapped for the first time the bioavailable ⁸⁷Sr/⁸⁶Sr in several geological zones in Tunisia.

The project was completed in May 2022, resulting in ten papers in leading international peer reviewed journals, three online databases, four open access best practice guides and two outreach books.

Human Jigsaw: Matching articulating skeletal elements from mass burials

The Human Jigsaw was a two-year project funded by the Horizon 2020 Marie Skłodowska-Curie individual fellowships (H2020-MSCA-WF-2018, Proposal: 867438). The overarching aim of this project was the development of novel techniques for sorting commingled human remains using the morphology of skeletal articulating surfaces, and the implementation of these techniques in key archaeological assemblages for addressing long-standing questions on the post-mortem treatment of the deceased.

In bioarchaeological contexts, multiple burials, typically leading to commingled remains from multiple individuals, have constituted a standard mortuary practice across the world throughout human history. Mortuary practices form an arena where social order is not only reflected but also potentially distorted or idealized by the living community in the process of negotiating social roles and identities. Thus, the study of multiple burials can offer insights into the sociocultural dynamics of the living communities. However, such a study poses serious challenges as the repeated use of a single burial site has often resulted in the very partial preservation of the skeletal remains. This poor preservation hinders the accurate estimation of the number of individuals represented in such assemblages, which forms the basis for any other bioarchaeological assessment. In forensic contexts, the deposition of bodies in mass graves has been common after warfare and natural disasters. In Cyprus, the events that took place in 1963-64 and 1974 have resulted in an unspecified number of individuals having been buried in mass graves, with an estimated 772 Greek Cypriots and 200 Turkish Cypriots still missing (Committee on Missing Persons: www.cmp-cyprus.org, accessed on 11/06/2023). Commingling is a major issue in forensic contexts and prevents the effective identification of each individual and the return of the bodies to the families.

Despite numerous proposed methods, commingling remains a pressing issue. Morphological reassociation of the elements that constitute a human skeleton is the most commonly adopted method, and osteometry is the main approach adopted as a means of quantifying morphological parameters. However, a major limitation of osteometric sorting methods is that they require excellent preservation of the human skeleton, whereas in commingled assemblages fragmentation is often extensive. Methods that could quantify the three-dimensional morphology of the articulating surfaces of major joints of the body could hold great potential in sorting skeletal remains given that diarthrodial joints are highly canalized, modular, and evolutionarily stable configurations.

This is the research gap that the Human Jigsaw aimed at filling through the use of Iterative Closest Point (ICP) algorithms and machine learning techniques. The focus was on matching the main elements of the lower skeleton (os coxae, femora, tibiae). The os coxae are the primary elements used in skeletal sex and age-at-death estimation, while the femora and tibiae provide the most accurate stature estimates. Therefore, by identifying these elements per individual, we readily obtain the three principal pieces of information required in any forensic and bioarchaeological analysis: sex, age-at-death and stature of the deceased. Indeed, the project has resulted in a major publication in the leading forensics journal (Journal of Forensic Sciences). Importantly, the fellow, Dr Maria-Eleni Chovalopoulou was appointed Assistant Professor of Biological Anthropology at the University at Athens, Greece, upon the completion of her fellowship. Therefore, the purpose of conducting high-standard research but also enhancing an early-career researcher’s chances of acquiring a tenure-track job in academia, has been successfully.

MetaMobility: Meta-analysis and agent-based modeling of human mobility in the Graeco-Roman world

MetaMobility is a two-year project funded by the Cypriot Research and Innovation Foundation in the context of the Excellence hubs call (EXCELLENCE/0421/0376). It aims at exploring human mobility in the Graeco-Roman world with a focus on the Hellenistic and Roman periods (4th c. BCE – 5th c. CE) in the Eastern Mediterranean through an integrated, interdisciplinary human osteoarchaeological, zooarchaeological, archaeobotanical, isotopic, economic-social historical and computational approach. In addressing this objective, MetaMobility also aims at generating open access resources for Graeco-Roman bioarchaeology (bibliographic databases for human osteoarchaeology, zooarchaeology and archaeobotany, databases of published bioarchaeological data for comparative analyses and meta-analyses) but also at producing a conceptual and methodological framework that allows for the constructive integration of textual evidence with bioarchaeological data.

Already notable progress has been made with regard to data collection and generation of databases for Graeco-Roman bioarchaeology, but also in scientific publications and outreach activities. In what concerns data collection, three graduate research assistants, in human osteoarchaeology, zooarchaeology and archaeobotany, have been compiling the titles and other metadata of published research on the above topics. The human osteoarchaeology assistant, Antonio Caruso, has developed Bi(bli)oArch-Italia (https://italia.biblioarch.com/), a bibliographic database for human bioarchaeological studies in Italy, chronologically covering skeletal assemblages from prehistory to early modern times. Subsequently, he identified 143 publications for the Hellenistic period and he has extracted all available data from 85 of them. For the Roman period, he has identified 319 publications and extracted data from 103. For archaeobotany, the research assistant, Panagiotis Koullouros, has identified 175 publications from the Graeco-Roman world and he has completed data extraction from 63 papers. For zooarchaeology, the graduate research assistant, Mahmoud Mardini, has identified 74 publications for the Graeco-Roman period and is currently extracting the data from them. The data collected by the research assistants refer both directly to mobility, which is the focus of this project, but also to pathology, diet, subsistence practices and mechanical stress, which are important in contextualizing the mobility data. In parallel, since January 2023, an Associate Research Scientist, Dr Chrysovalantis Constantinou, has been working on agent-based modelling in order to simulate Graeco-Roman mobility patterns. This task is performed in close consultation with scientific advisory member Dr Ruben Post (History Lecturer at the University of St Andrews).

Although MetaMobility focuses on already published data, our team is also strongly involved in the generation of important new datasets from Graeco-Roman assemblages in Italy (Sicily), Greece (Attica, Thebes) and Lebanon (Tyre, Beirut and Byblos). Moreover, given the major limitations imposed by the use of different recording protocols in skeletal data collection, which restricts the use of published data as comparative material, our team has developed an open-access resource for data collection and sharing (STARC OSTEOARCH). This initiative is currently under review for publication.

Results of the project to date have been disseminated in four scientific papers, one book chapter and conferences/invited lectures. Importantly, the PI was recently invited by the De Gruyter publishing house to author a monograph on The bioarchaeology of the Greco-Roman society for a new series that they recently launched with the title Trends in Classics – Key Perspectives on Classical Research.

RECONSTRUCT: Reconstructing fragmented bones, reconstructing fragmented lives

MARIE SKŁODOWSKA-CURIE ACTIONS Research Fellowship Programme – European  AcademyRECONSTRUCT is a two-year project funded by the Horizon Europe Marie Skłodowska-Curie postdoctoral fellowships (HORIZON-MSCA-2022-PF-01-01, Proposal: 101104702). Human skeletal remains can offer key information on diverse aspects of past life but, like all archaeological materials, they only give a glimpse into the life of past individuals; hence, a fragmented perspective into our ancestors’ lives. Their interpretative potential is greatly inhibited by the fact that such remains are often found fragmented due to several anthropogenic and natural taphonomic agents, such as funerary treatment, animal activity, soil pressure and others. This fragmentation severely limits the information that may be extracted from human bones in terms of metric analysis, geometry and morphology. RECONSTRUCT aims at producing 3D morphable models for the main elements of the lower and upper limbs of the human skeleton, which will be then used to infer the missing morphology of fragmented or incomplete bones. In order to achieve this aim and address a major current limitation in human skeletal analysis, RECONSTRUCT will integrate approaches from osteoarchaeology, forensic anthropology, biology, engineering, and data science. The results of the project will maximize the information that may be extracted from bioarchaeological research, contributing to a more comprehensive assessment of past life parameters. RECONSTRUCT will also have major implications in forensic anthropology since the study of modern skeletal remains suffers from similar limitations in terms of partial preservation as those witnessed in archaeological bones. Finally, the source code and raw data emanating from RECONSTRUCT will be made open access, greatly enhancing the extension of this approach to zooarchaeology, palaeoanthropology, and the prosthetic implants industry.

The project was initiated in June 2023 and the fellow, Dr Andreas Bertsatos, has already created his own equipment for the effective photogrammetric capturing of the 3D morphology of human long bones. In addition, he has started systematic data collection from major Mediterranean documented skeletal collections. During the stage of data analysis, close collaboration is foreseen with the Computation-based Science & Technology Research Center of The Cyprus Institute.