|At the beginning of the fourth century, Christians already constituted a substantial proportion of population of the Roman Empire, especially in eastern provinces, but also in Italy, north Africa or Spain. With its origins in 1st century Palestine, Christianity reached some locations earlier than others and blossomed in some places better than others. Using network analysis and computational models of the diffusion of innovations, our research project aims to evaluate several factors which could be responsible for the observed temporal and spatial distributions. We hypothesize that the scarcely evidenced temporal and spatial distribution of Christianity over the Roman Empire can be re-grown in an artificial simulation environment as a diffusion of innovation model on a Roman travelling network of roads and maritime routes, which connects respective settlement sites to one another. We consider only (1) the travel expenses, (2) population sizes and economic importance of reachable destinations and (3) exponential grow of Christian number, while all the other environmental variables can be ignored for the sake of the analysis. In the Graeco-Roman context, an adherence to a religious cult was typically expressed by one’s inclusion in a certain social unit (extended family, association etc.), rather than by personal decision and commitment to a set of beliefs. Therefore, Christianisation, too, can be approached on the level of practices of social groups instead than on the level of decisions of individuals. In that respect, by Christianisation we mean a twofold process: 1) by horizontal Christianisation we refer to a process concerning how worldviews and ritual innovations spread from one group to another; 2) by vertical Christianisation we refer to a process, not a moment, of continuous implementation of these innovations into the social practice of certain social group. At the current state of research, we are focusing more attention on the horizontal aspect.