A range of evidence exists demonstrating that social capital is associated with a number of important economic outcomes such as economic growth, trade and crime. A recent literature goes further to illustrate how historical events and variation can lead to the development of differing and consequential social norms. This paper examines the related questions of how persistent initial variations in social capital are, and the extent to which immigrant groups, do or do not converge to the cultural and social norms of their recipient country by examining a unique and geographically concentrated immigration event in 16th century Italy. We demonstrate that despite the substantial time since migration these communities still display different behaviour consistent with higher civic capital than other comparable Italian communities. Moreover, we demonstrate that this difference does not appear to have changed over the last 70 years. For instance, differences in voter turnout apparent in the late 1940s remain in the 21st century. This latter finding has implications for our view of the likelihood of assimilation of immigrant groups to local norms, particularly in cases of large-scale migration.