Economic integration, defined as a process of economic unification of national economies, has been going on all through modern European history. 1 Two factors have always stimulated integration:

Technical progress. Mechanisation and automation of the production process have completely changed production methods. Advances in energy technology, for instance, led to the replacement of human and animal power with steam and, later, with electricity. With respect to transport, horse-drawn vehicles gave way to railways and lorries. As a result, goods can be produced and distributed cheaply in large numbers.

Political idealism. Since the Middle Ages there has been virtually no period in which statesmen or philosophers did not point to the common European heritage and the necessity for more ‘political’ unity in Europe. 2