1 LAC2014 Proceedings | DOI 10.5463/lac.2014.62 Abstract In this paper we present the first results of a study that aims to better understand and model the size and development of population in the Dutch Roman limes zone, as part of a larger research project investigating the development of the cultural landscape in the area. Earlier estimates of population size have only used general assumptions based on settlement density and supposed Roman army recruitment requirements and have not considered in any detail the factors influencing population growth and decline. This paper first presents the existing evidence for estimating population size in the area and then discusses the evidence for mortality and fertility estimates in the Roman period, necessary to better understand the large-scale demographic processes involved. From this evidence, new estimates for population size in the Early and Middle Roman period are calculated, using agent-based modelling to better understand the dynamics of population growth and the effects of recruitment of soldiers by the Roman army. It is concluded that earlier calculations underestimated the potential for population growth as well as the effect of forced recruitment on demography. Keywords: Roman limes, Dutch River Area, Batavians, Demography, Agent-Based Modelling Introduction The Finding the limits of the limes project aims to apply spatial dynamical modelling to reconstruct and understand the development of the cultural landscape in the Dutch part of the Roman limes zone (fig. 1). It focuses on modelling economic and spatial relations between the Roman army and the local population, in particular the interaction between agriculture, animal husbandry and wood management, and the related development of settlement patterns and transport networks in the area. In this paper we will focus on one of the most debated but also least understood issues involved, the demographic development during the Roman period. Various authors (Bloemers, 1978; Willems, 1986; Vossen, 2003) have published estimates of population densities for the Early Roman B and Middle Roman A periods (AD 25-150) for which most of the archaeological evidence is available. These periods are characterised by a significant increase in number and size of settlements especially after circa AD 85 when the area was fully integrated in the Roman Empire. However, the published estimates are not based on a good understanding of the demographic processes involved and do not shed much light on the interplay between natural population growth, migration, and recruitment of (especially) Batavian Modelling the Dynamics of Demography in the Dutch Roman Limes Zone Philip Verhagen Vrije Universiteit Amsterdam, Faculty of Humanities, The Netherlands email: j.w.h.p.verhagen@vu.nl Jamie Joyce Vrije Universiteit Amsterdam, Faculty of Humanities, The Netherlands email: j.a.joyce@vu.nl Mark Groenhuijzen Vrije Universiteit Amsterdam, Faculty of Humanities, The Netherlands email: m.r.groenhuijzen@vu.nl