Simulating Roman Economies is a manifesto for the use of computational methods in Roman economic history. It argues convincingly that Roman economic historians should embrace computational modelling as a mainstay in the field. This is an important message, which makes the volume a significant contribution to the field, and the initiative of the editors deserves applause.

The focus of the volume is on simulation, which is defined as ‘a formal model representing the operation or behaviour of a system or process where the functioning of the model over time is made explicit’ (6). Tom Brughmans’ introductory chapter argues that simulation is both necessary and beneficial for Roman economic historians. It is a necessity because the Roman economy was a complex system, the study of which requires complicated theories that are best implemented through formal modelling. And it is beneficial as it not only serves as a tool for understanding the past but also opens up new avenues for research (e.g. for data collection or by raising new questions) and leads to constructive theoretical multivocality, moving away from traditional debates between extreme standpoints.

The body of the volume consists of ten chapters presenting different case studies of simulations of various aspects of the Roman economy. The subjects cover a wide range, from agricultural production, transport networks and trade to demography and epidemiology. Scholars and experts from many different subfields will find something to their interest in the volume.

The tone of the volume is overtly positivist. The benefits of the use of simulation are consistently foregrounded. Some of the chapters are very successful in demonstrating how formal approaches can make meaningful and important contributions to existing historical debates. Marek Vlach, for example, shows that considering regional variations in population and infrastructure densities, as well as environmental factors, lends more credence to the lower end of earlier estimates of the overall demographic impact of the Antonine Plague. While the idea that the pandemic would have affected different parts of the empire very differently is widely accepted, this simulation is the first study to demonstrate why this matters.

While the overall argument for the potential of simulation is convincing, the volume also highlights the challenges that come with the upsurge of innovative, more technical methodologies in a predominantly conservative field. Accessibility is a crucial point. In order for simulations (or any type of computational modelling) to take firm root within the field, the results of these studies need to be accessible to scholars far beyond the small group of experts acquainted with the methodological technicalities. This presents a significant challenge as it is not easy to make results based on complex computational techniques understandable to a non-expert audience, let alone a sceptical audience (which is sometimes the case in our field). The editors addressed this challenge by asking the contributors to present their results in ‘non-technical language in ways that might convince scholars in classical studies’ (29). In line with these instructions, most chapters are not burdened by too-detailed descriptions of the technicalities, which are instead efficiently relegated to the footnotes and references. Good examples include the chapters by Simon Carrignon and collaborators (on the buying strategies of tableware traders) and Brian Dermody and co-workers (on the production and trade of grain). This is a good choice which increases the readability of the chapters enormously.

Despite these efforts, some of the chapters will probably still be quite heavy on the stomach for readers without any familiarity with the modelling technique(s) they employ. These chapters might have appealed to a wider audience if they had given more attention to the broader historical context and implications of the simulation results. Most non-expert readers will simply take the model as a black box and fast-forward to the results, judging them on their overall plausibility and significance within existing historiographical frameworks. For that reason, positioning the simulation results within existing debates is paramount to engage these readers. The chapters by Pascal Warnking (on the simulation of sailing times and shipping routes) and Xavier Rubio-Campillo and María Coto-Sarmiento (on the use of formal hypothesis-testing frameworks), for example, both discuss a number of interesting case studies. But less would probably have been more in these chapters. Focusing on fewer examples would have allowed the authors to delve deeper into the underlying historical questions and thus engage a wider readership.

The two chapters on Roman transport systems together might show the way forward. Mark Groenhuijzen showcases the effective use of computational methods in studying local transport systems (his focus is on the Dutch part of the Lower Rhine limes), while the chapter by Pau de Soto and César Carreras (on the Roman transport network of the Iberian peninsula) dedicates considerable attention to the historical context. Together, these chapters demonstrate how simulation studies can provide valuable insights and be effectively communicated.

Several other chapters are very dependent on earlier work by their authors, which may make them hard to digest for non-specialists. Examples include the simulations discussed by J. W. Hanson and Tom Brughmans (on settlement scale and economic networks), Philip Verhagen (on the demography of the Dutch limes) and Shawn Graham (on Peter Bang's model of the Roman economy as a bazaar). The first two are elaborated versions of existing models (T. Brughmans and J. Poblome, Antiquity 90 (2016), 393–408; and P. Verhagen et al., LAC 2014 proceedings (2016), 1–13, respectively) while the latter is a reflection on an earlier modelling study (S. Graham and S. Weingart, J. Archaeol. Method Theory 22 (2015), 248–74). Being familiar with the earlier versions of these models is highly beneficial, almost essential, for a thorough understanding of the discussions presented in this volume.

Over the last decades, a gap has begun to form between traditional historians and neoteric modellers. With the array of computational methodologies and techniques expanding rapidly, the gap is widening quickly. To avoid a rift within the field, both sides will need to make an effort. On the one hand, modellers need to keep on working hard to make their findings accessible to non-experts. This is a laborious but important endeavour. On the other hand, as also argued by Andrew Wilson in his concluding chapter, new generations of ancient historians and archaeologists should be exposed more formally during their education to the use of computational methods. This will make the classicist of the future more receptive to modelling studies. With the commitment of both sides, we can bridge the gap. The present volume serves as a guide for those scholars (present and future) who aim to reunite the field.