This chapter sets out to conceptualise the institutional and legal evolution of the European Communities (EC) over time from the Treaties of Paris and Rome to the Treaty of Maastricht.

The founding treaties of Paris and Rome were essentially open-ended efforts for integration, despite their undeniable differences in nature. At the moment of negotiating the founding treaties and during the first years of the Communities, it was unforeseeable whether the Communities would go through a process of gradual and increasing federalisation, or whether member states would eventually manage to dominate the Communities. The balance between these contradictory tendencies inherent in the founding treaties was clarified only through the open political battles in the 1960s. In a sense, the battle between federalist and intergovernmentalist streams has continued beyond Maastricht to the present day.