The project will study the history of codification, i.e. large scale legislation containing an inherent system, from 1800 to the present in France, Germany, Belgium, the Netherlands and the UK. The project will look at a block of countries, so that it can take into account the entanglements of the codification history in these countries and thus correct the current historiography, mainly written from a national or even nationalistic perspective. Moreover, entanglements do not only link countries, but also branches of law. Therefore, the project will study private law in its broadest sense, including commercial law and the history of civil procedure. This approach will lead to an integral legal history which, without excluding other elements, at least takes into account all the relevant aspects of legal evolution. By looking at several countries and branches of law, the project will also avoid extrapolation from a too small set of cases, which has led current historiography to pose ‘universal truths’ based on the situation in one country or branch of law and for which many examples to the contrary exist in other countries or branches of law. The project will use process tracing in order to better identify the relevant causes and distinguish between the functional and contextual causes that determine the outcome of a codification process. The former are to be explained by the common goal of codification and can be generalized, whereas the latter are contextually determined and specific to a particular case. The project will elaborate this distinction and place it within a more explicit theoretical framework, which can also inspire other comparative legal historians. The project has not just a historiographical and theoretical relevance, as many countries are now recodifying and jurists regularly debate on the need of common codes for Europe.