The European Parliament, with its predecessor being the Common Assembly of the European Coal and Steel Community, has a long history. It is one of the oldest community institutions, together with the High Authority, now known as the Commission; the Council of Ministers; and the European Court of Justice. From the very beginning, Christian Democrats, conservatives, socialists, Social Democrats and liberals from the founding member states advocated establishing a European parliamentary system with its own budget and specific procedures.

Over the course of time, a range of efforts and numerous initiatives by various parliamentary groups have forced the heads of state and government to grant the EP ever more rights. Even before the first direct elections in 1979, the representatives had already achieved respectable successes. The close cooperation of the groups across the political and ideological divides has been decisive, with there always having been a fundamental pro-European consensus among the Members of the European Parliament on the need for Europe’s unification. Both in the context of crises and in the course of the enlargements from 6 to 27 members, a growing number of tasks and challenges have not been able to be solved on a purely national level.

As a result, there has been a continual need to further legitimise decision-making through the introduction of increasingly democratic parliamentary processes; this has enabled the EP to acquire more and more opportunities for co-decision. During this process, European Christian Democrats, in particular, have played a major role. In the face of the recent onslaught from EU opponents and populists, the European People’s Party has held the European flag high, while also defending and strengthening the EP, the development of which represents one of the greatest achievements of European unification.

This paper attempts to periodise this evolution of the Parliament.