Europe's 'political space', its dimensionality and its impact on European policies have received increased academic attention lately. Yet, one very basic element of this political space, the party composition of EU member states' governments, has never been studied in a systematic way in the rich literature on European integration. In this paper we explain why the EU literature should pay more attention to the analysis of Europe's party-political 'centre of gravity'. We give a systematic overview of the party composition of member governments from 1957 to 2003. This includes analyses of how the support for integration, the left/right political conviction, and the ideological homogeneity or heterogeneity of the member states affected the Council over the course of time. We draw on expert surveys, the data of the Comparative Manifesto Project, and data about government composition.