During this time, Adenauer came into conflict with the Economics Minister Ludwig Erhard over the depth of German integration to the West. Erhard was in favor of allowing Britain to join to create a trans-Atlantic free trade zone, while Adenauer was for strengthening ties amongst the original founding six nations of West Germany, France, the Netherlands, Belgium, Luxembourg and Italy. In Adenauer's viewpoint, the Cold War meant that the NATO alliance with the United States and Britain was essential, but there could be no deeper integration into a trans-Atlantic community beyond the existing military ties as that would lead to a "mishmash" between different cultural systems that would be doomed to failure. Though Adenauer had tried to get Britain to join the European Coal and Steel Community in 1951–52, by the early 1960s Adenauer had come to share General de Gaulle's belief that Britain simply did not belong in the EEC. The Élysée Treaty was signed in January 1963 to solidify relations with France.