Least-Cost Networks and Network Analysis: Modelling trade relations in early medieval East Central Europe
Donat Wehner
Abstract Medieval trade relations can be considered from many different angles. One can attend to the actors, their identities, motivations, manners and perception as well as the circumstances of travelling and equipment or one can deal with types and amount of traded goods, to name just a few of the possible aspects. The concern of this contribution is to reveal the structures, intensities and directions of commodity flows on different spatial and temporal scales in East Central Europe in the Early Middle Ages. Networks of nodes and edges serve as visualizations of the economic relations. Sites with an increased density of interaction function as nodes, economic flows on transportation routes between these nodes serve as edges. The commodity flows can be weighted asymmetrically as well as differentially. Starting from networks created from least cost path routes and graph theoretical models network analysis and space syntax are used to obtain additional information on the structural characteristics and mechanisms of the networks. One issue is the network density. Are there many trade relations or rather few? Bridges and structural gaps are of interest as well. Do sites exist which connect economically densely entangled areas and where are such areas not connected? The importance of different sites in the exchange-networks is also relevant. It can be defined e.g. by the amount of relations (degree centrality), the closeness to other interaction hubs (closeness centrality) or in its strategical position between other interaction hubs (betweenness centrality). In order to achieve a dynamic and differentiated result, multiplex multimodal network analysis is used. Different artifact-groups like coins, so called imports, scales and weights as well as geographical distances and written sources of trade relations in diverse place-time-configurations are included as representatives and parts of trade. By combining various relevant models, data records, spatial layers (local, regional, supra-regional) and time slices, dynamic networks can be created and interpreted in a comparative and complementary way. This approach provides an opportunity for understanding the significance of relationships within and between past material culture, individuals, and groups. The alternating relation between physical distance, commodity distribution and contemporary perception of commodity flows can for example be identified by using affiliation-networks of Least-Cost Path relations, artifact-relations and trade relations known from written sources. One gets an idea of different types of linking in the context of trade activities, what they are good for and how they are related to each other. Thereby, connections in the network can be favored, created or handicapped and impeded by space. Complex feedback-loops between the creation of space through networks and the creation of networks through space can be observed. By doing so, mediation between physical and social space is created similarly.
