The aim of this article is to analyse the relationships between law and conventions with regards to an issue still little explored in the perspective of the Economics of Convention (EC): the history of property rights. Focusing on Continental Europe, the main key points of the recent debate on property rights’ long-term evolution will be outlined, which are basically developed along the lines of the New Historical Institutionalism theories (NHI). After discussing the NHI approach to legal institutions, it will be demonstrated how even the soundest criticisms to this approach do not exhaust the list of open questions on the relationship between conventions and property rights. These questions are mainly related to the problems of uncertainty and to the connection between property rules, their interpretation and their legitimization. By defining these questions, it will be shown how the EC perspective could contribute to providing a more complex interpretation – and therefore historically more pertinent – of the long-term changes of one of the major legal institutions of western capitalism.