The EUPOL (Version 5) dataset includes virtually all information contained in the European Commission’s online database PreLex. The mission of PreLex was to monitor the inter-institutional decision-making process of the EU, providing information about various formal events and institutional actors involved in policy-making, as well as cross-references to documents contained in other online databases. In combination with its long-term coverage, starting in the mid 1970s, PreLex is a useful source of information for studies of long-term developments in EU politics and European integration.