Tom Brughmans

Roman bazaar or market economy? Explaining tableware distributions through computational modelling

Abstract How closely integrated were the commercial centres of the Roman world? Were traders aware of supply and demand for goods in other cities, or were communities of traders in cities protectionist and working opportunistically? Widely traded commodities such as terra sigillata tablewares in the Eastern Mediterranean provide an ideal opportunity to explore the economic processes that underlie the archaeological evidence. Agent-based computational modelling allows various such processes to be explored, and also identifies areas for further investigation.

Complex networks in archaeology: urban connectivity in iron age and Roman southern Spain

In this article the authors highlight some of the issues surrounding the study of past urban connectivity and how archaeologists can deal with them by adopting a complex networks research perspective.

Exploring Transformations in Caribbean Indigenous Social Networks through Visibility Studies: the Case of Late Pre-Colonial Landscapes in East-Guadeloupe (French West Indies)

This paper presents a study of the visual properties of natural and Amerindian cultural landscapes in late pre-colonial East-Guadeloupe and of how these visual properties affected social interactions. Through a review of descriptive and formal visibility studies in Caribbean archaeology, it reveals that the ability of visual properties to affect past human behaviour is frequently evoked but the more complex of these hypotheses are rarely studied formally. To explore such complex hypotheses, the current study applies a range of techniques: total viewsheds, cumulative viewsheds, visual neighbourhood configurations and visibility networks. Experiments were performed to explore the control of seascapes, the functioning of hypothetical smoke signalling networks, the correlation of these visual properties with stylistic similarities of material culture found at sites and the change of visual properties over time. The results of these experiments suggest that only few sites in Eastern Guadeloupe are located in areas that are particularly suitable to visually control possible sea routes for short- and long-distance exchange; that visual control over sea areas was not a factor of importance for the existence of micro-style areas; that during the early phase of the Late Ceramic Age networks per landmass are connected and dense and that they incorporate all sites, a structure that would allow hypothetical smoke signalling networks; and that the visual properties of locations of the late sites Morne Souffleur and Morne Cybèle-1 were not ideal for defensive purposes. These results led us to propose a multi-scalar hypothesis for how lines of sight between settlements in the Lesser Antilles could have structured past human behaviour: short-distance visibility networks represent the structuring of navigation and communication within landmasses, whereas the landmasses themselves served as focal points for regional navigation and interaction. We conclude by emphasising that since our archaeological theories about visual properties usually take a multi-scalar landscape perspective, there is a need for this perspective to be reflected in our formal visibility methods as is made possible by the methods used in this paper.

Visibility Network Patterns and Methods for Studying Visual Relational Phenomena in Archeology

A review of the archaeological and non-archaeological use of visibility networks reveals the use of a limited range of formal techniques, in particular for representing visibility theories. This paper aims to contribute to the study of complex visual relational phenomena in landscape archaeology by proposing a range of visibility network patterns and methods. We propose first- and second-order visibility graph representations of total and cumulative viewsheds, and two-mode representations of cumulative viewsheds. We present network patterns that can be used to represent aspects of visibility theories, and that can be used in statistical simulation models to compare theorised networks with observed networks. We argue for the need to incorporate observed visibility network density in these simulation models, by illustrating strong differences in visibility network density in three example landscapes. The approach is illustrated through a brief case study of visibility networks of long barrows in Cranborne Chase.

MERCURY: an Agent-Based Model of Tableware Trade in the Roman East

A large number of complex hypotheses exists that aim to explain aspects of the Roman economy, consisting of many explanatory factors that are argued to affect each other. Such complex hypotheses cannot be compared or tested through the traditional practice of qualitative argumentation and comparison with selected small sets of written and material sources alone. Moreover, these hypotheses often draw on different conceptual frameworks to abstract the same past phenomenon under study, hampering formal comparison. There is a need in the study of the Roman economy for more formal computational modelling for representing and comparing the many existing conceptual models, and for testing their ability to explain patterns observed in archaeological data where possible. This paper aims to address this need. It argues that communicating the potential contribution of computational modelling to scholars of the Roman economy should focus on providing theoretically well-founded arguments for the selection of the included and excluded variables, the conceptualisation used, and to address those elements of conceptual models that are at the forefront of scholarly debates. This approach is illustrated in this paper through MERCURY (Market Economy and Roman Ceramics Redistribution, after the Roman patron god of commerce), an agent-based model (ABM) of ceramic tableware trade in the Roman East. MERCURY presents a representation of two conflicting conceptual models of the degree of market integration in the Roman Empire, both of which serve as potential explanations for the empirically observed strong differences in the distribution patterns of tablewares. This paper illustrates how concepts derived from network science can be used to abstract both conceptual models, to implement these in an ABM and to formally compare them. The results of experiments with MERCURY suggest that limited degrees of market integration are unlikely to result in wide tableware distributions and strong differences between the tableware distributions. We conclude that in order for the discussion on the functioning of the Roman economy to progress, authors of conceptual models should (a) clearly define the concepts used and discuss exactly how these differ from the concepts used by others, (b) make explicit how these concepts can be represented as data, (c) describe the expected behaviour of the system using the defined concepts, (d) describe the expected data patterns resulting from this behaviour, and (d) define how (if at all) archaeological and historical sources can be used as reflections or proxies of these expected data patterns.

The Case for Computational Modelling of the Roman Economy: A Reply to Van Oyen

We thank Astrid Van Oyen for a highly constructive and important discussion piece that will improve our own future work, as well as that of others. We wish to elaborate on one issue: that formalist approaches do not necessarily have inherently modernist theoretical assumptions.

Carl Knappett. An archaeology of interaction: network perspectives on material culture and society . x+251 pages, 50 illustrations. 2011. Oxford: Oxford University Press; 978-0-19-921545-4 hardback £ 60.

As one might expect, the picture has become sharper and also more complex in the wake of the analytical programme. The current suite of analyses not only distinguishes two basic chemical compositions (labelled α and β) in western Crete, but petrography suggests three or four fabrics within them. Significantly, another chemical type, classified in the 1970s as indistinguishable between central mainland Greece (Boeotia) and central Crete, can now be separated, again with the assistance of petrography, into Cretan (the majority) and mainland origins. There is a good overall ‘fit’ between the three techniques.