On 14 January 1964, addressing the Consultative Assembly of the European Council, the Belgian Foreign Minister, Paul-Henri Spaak, challenges the idea that the Community of the Six is a failure and calls for enhanced European unity.

Dans ses Mémoires, Robert Marjolin explique l'origine des crises successives qui ont secoué la Communauté économique européenne (CEE) au cours des années soixante.

On 21 May 1964, Johannes Linthorst Homan, Netherlands Member of the High Authority of the European Coal and Steel Community (ECSC), addresses the Geneva Branch of the Union of European Federalists about the difficulties involved in and hopes for European integration.

Working session of the members of the Commission of the European Economic Community (EEC) in office from 10 January 1958 to 6 July 1967, under the presidency of Walter Hallstein. From left to right (starting with Sicco Mansholt, on the left, with his pipe): Sicco Mansholt, Robert Marjolin, Lambert Schaus, Lionello Levi Sandri, Guido Colonna di Paliano, Hans von der Groeben, Walter Hallstein, Émile Noël, Executive Secretary of the Commission, and Jean Rey.

In his Memoirs, Johannes Linthorst Homan, former Netherlands Member of the High Authority of the European Coal and Steel Community (ECSC), recalls the institutional crisis that shook the European Community in 1965–1966.

During an interview broadcast on 18 September 1964 on RTL radio, Paul-Henri Spaak, Belgian Foreign Minister, proposes to his partners that the Fouchet Plan be relaunched in order to rouse the Europe of the Six from the slumber into which it seems to have settled.

On 1 July 1965, Walter Hallstein, President of the European Commission, takes stock of the situation in Europe following the meeting of the Council of Ministers on 30 June and 1 July 1965.

On 16 July 1965, the Italian daily newspaper Corriere della Sera analyses the political and economic causes of the internal crisis affecting the European Economic Community (EEC).