Population-Area Relationship in Medieval European Cities

We examine the relationship between population and settled area in a sample of 169 European cities from the early fourteenth century. We compare two behavioral models which make differing predictions regarding the quantitative form of this relationship. The social reactor model is based on movement and interaction within the urban built environment and has been applied successfully to contemporary cities. This model predicts a sublinear scaling relationship; i.e., that cities should become increasingly dense as they grow. The alternative structured interaction model, derived for the first time in this paper, is based on the assumption that social interactions are strongly channeled by hierarchical social institutions. This model predicts that agglomeration effects should be attenuated in accordance with the strength of institutional constraints. Our results are more consistent with the social reactor model. Although social life in medieval cities was certainly influenced by hierarchical institutions (e.g., guilds, the church, municipal organizations), the effects of these institutions for agglomeration effects appear to have been decidedly secondary. Given the convergence of the medieval data with patterns observed in studies of contemporary urban systems, we suggest urban life in both settings can be modeled using a single theoretical framework. Our results support the hypothesis that cities throughout history share key social networking processes that generate scaling regularities.