The Science of Roman History: Biology, Climate, and the Future of the Past

Sometime in the future, scholars of the Roman world will be as conversant with stable isotopes and alleles as with inscriptions and coins. Scheidel’s edited volume aims to accelerate the integration of palaeoscientific data into Roman studies, offering seven stand-alone chapters that outline the state of science-based research about the ancient past and its most significant findings. With a blend of historians, archaeologists, and scientists contributing, this collection is a methodological mosaic that highlights the growing utility of unconventional evidence such as glaciers, fossilized plant seeds, animal bones, human teeth, and DNA. Rather than a concerted thesis, these essays together illuminate the broad potential of scientific inquiry to shift existing or generate new narratives about people and places previously rendered silent by an absence of legible texts and objects. While the work optimistically celebrates paleoscience, it also points to some of the difficulties of applying a natural archive to conventional rhythms of Roman history.

The fusion of science and history works best in the chapters centered on archaeobotany and zooarchaeology, penned by van der Veen and MacKinnon, respectively. Both offer theoretically sophisticated portraits of how fragments of plant and animal remains can contribute to a better understanding of historical issues like imperialism, class construction, and economic networks. Van der Veen explains, for instance, how the transition from hulled to naked wheats across the empire embodies a cultural turn that privileged fluffy bread over a tenacious, drought-resistant staple plant. It intimates productive strategies that shifted from the primacy of risk-averse producers to the dietary concerns of a pretentious elite. Bugs also evolved in response to Roman grain; changes in fossilized insect carcasses reveal a community’s shift to larger silos, structures meant to facilitate storage patterns necessary for participation in the Roman state. MacKinnon’s chapter highlights the utility of animal bones, whose stable isotopes (registered as varying amounts of carbon, nitrogen, strontium, and oxygen) make legible the ecologies traversed by the animal before butchery, thereby illuminating patterns of its human master. Zooarchaeologists have also intervened in seemingly unlikely subfields, including Roman religion; for example, Apollo preferred cuts of meat from the right side of an animal carcass, a bias that has interesting implications for interpreting cult practice and space.

Two chapters focus on the study of human bones and teeth. The first, by Sperduti, Bondioli, Craig, Prowse, and Garnsey, offers a state of the field review for paleodemography. These scholars can ascribe sex to the owner of a particular bone with some confidence, but determinations of age at death and cause of death remain more tenuous and depend heavily on comparative deposits. Because maladies like osteoporosis appear more readily on certain joints, the authors say, the likelihood of such a diagnosis is statistically dependent on the survival of those joints—thus, the irregular nature of bone survival presents several problems for making blanket determinations about the health of Roman populations. As with animal bones, one of the most promising avenues in this field builds on the study of stable isotopes that accrue on bones and reflect a body’s ecological setting before expiration. Using such modes of inquiry, paleodemographers can discern important findings about migration, for example that one-third of the burials in Roman Portus belonged to people not originally from the area of the Tiber’s mouth. The other osteocentric chapter, by Gowland and Walther, focuses on human stature as a marker for health. The growing understanding that non-nutritional elements, including genetics and social factors, bear greatly on stature has complicated this avenue of inquiry. Further, the authors consider previous methodologies that estimated stature based on the length of a femur or tibia unreliable, as they were based on long bones that tend not to display periodic dietary stress. The authors advocate for osteological analysis that incorporates multiple techniques and a “life-course” perspective, as opposed to a snapshot. Over the long term and across the empire’s vast domain, demographers have identified one significant pattern with some regularity: exposure to Roman hegemony suppressed a community’s health.

A chapter about ancient DNA (code preserved in archaeological, paleontological, and museum sources), by Tuross and Campana, outlines the science behind genetic mapping and the recent history of detecting salient patterns in aDNA. Some of the earliest results have focused not on ancient Romans but on genetic relationships between ancient Etruscans and modern Tuscans and kinship patterns in Egyptian mummies. The authors also touch on an important area of research for Roman antiquity: mapping the genetic identity of the bacterium responsible for the Justinianic Plague. Results have shown that some victims of the sixth-century disease suffered from a strain of Yersinia pestis, the primary bacterium behind the fourteenth-century Black Death. Its phylogenetic tree, however, reveals that the sixth-century iteration was a different evolutionary branch of the disease, limiting the degree to which we can extrapolate its impact based on later pandemics. The following chapter, from King and Underhill, explains how the study of paternally transmitted Y chromosomes in modern populations betray long-term genetic trends. In fact, about 190,000 years of sequencing has been mapped, revealing moments of convergence and divergence in human populations. Such insights are useful for detecting the impact of ice ages or the Neolithic Revolution on our species, but the data remains too granular for application on the scale of Roman history.

Harper and McCormick’s chapter centers on the ancient climate and points to the explosive potential for scientific data to address big changes, like vacillations of an empire. Because climate encompasses so many different facets—temperature, precipitation, solar irradiance—generating a profile of the ancient climate entails compiling a vast range of proxy data from sources like trees, glaciers, and speliothems. The multiplicity of natural archives allows the authors to highlight significant convergences from discrete sources, chronological points where rapid climate change left its imprint in a variety of ways. Harper and McCormick seek consilience by matching the sharpest shifts with changes in the historical record, thus offering a chance (for themselves and readers) to grapple with the process of synthesizing paleoscience and human events. Their data is marshaled to proffer a notion that Roman hegemony waxed and waned in concert with climate stability and instability—a change in fortune related to food stability, they say. Scholars have long speculated about the relationship between the environment and Rome’s decline, but a clearer, more comprehensive picture of changes in the land enlivens this debate and invites deeper engagement. To their credit, the authors adopt an apprehensive tone, knowing well that graphs indicating climate change do not, by themselves, explain political fragmentation. Indeed, some historical evidence fits awkwardly with the hypothesis. Undoubtedly, Roman power was wobbly around the edges in the fourth and fifth centuries, but emperors also doubled down on food distributions at the capitals in this period; Constantinople began its own annona in the early fourth century, while Rome added the meat of South Italian pigs to the already extensive menu of bread, wine, and olive oil. Further, without the bias of Gibbonian hindsight, we might imagine that the Roman empire’s highly developed system for moving foodstuffs insulated it against disruptions in supply, giving it a decisive advantage in this period over smaller, more localized regimes, such as the Franks and the Huns.

This book is deliberately transitional in nature, a plea for more integration of science into Roman studies. In that sense, it would have benefited from a short section at the end of each chapter that addressed where the field should go next in that area. The chapters also lack a shared idiom, likely because the most obvious umbrella for these works, environmental history, has not yet achieved purchase in Roman studies. Earlier environmental histories of the Roman world relied heavily on literary accounts—the classic works of Donald Hughes and Clarence Glacken, for instance—so there are few existing models for how to incorporate paleoscience and explain the interaction of ecology and culture. One example the field might follow is Hoffmann’s survey of medieval Europe (An Environmental History of Medieval Europe [Cambridge 2014]). Hoffmann’s environmental history privileges the kind of paleoscience featured in Scheidel’s volume and brilliantly recasts familiar medieval cultural structures (Christianity, land tenure, urbanism) in ecological terms. A synthetic Roman environmental history will be a challenging project, as it must encompass a massive, complex geography; it will also be deeply relevant for nearly all aspects of empire, since state initiatives left an environmental mark nearly everywhere. Although much remains to be done, this collection demonstrates the promise of paleoscientific inquiry and articulates the importance of scientific legibility for the future of Roman studies.

Benjamin Graham
University of Memphis
bjgraham@memphis.edu