Abstract The development of the “public sphere” and the Enlightenment are closely related to the networks of publishers involved in print culture. In Britain, a key question is whether diversity (in terms of nationality) in publishing increased over time. In this paper, we use large-scale library catalog data and a class of models known as Exponential Random Graph Models (ERGMs) to investigate the extent to which an 18th-century network of publishers in London was homophilous with respect to nationality, and specifically investigate whether those with close publishing connections to Scotland formed a separate group or if they were simply integrated into the London book market. As there is little external information on the majority of publishers, we generate node and edge attributes from the catalog data itself. The results suggest that social processes were deeply involved in the decisions behind copublishing and collaborations and that there is indeed a significant positive effect on tie formation if both nodes are “Scottish” publishers, though this lessens over the century. We find that other important factors in tie formation are edgewise shared partners and similarity in patterns of genres published.