In the first centukry AD, a merchant setting off from Rome on a journey to Cologne was able to pay his bills with the same coin, the denarius, over his entire journey.
Initially, Rome safeguarded cohesion of its large empire by fire and sword, then increasingly by placing even the most remote provinces under the legal system and administration of Rome.
The precise lessons to be drawn from such historical episodes may not be entirely clear.
Professor Otmar Issing, Member of the Executive Board of the European Central Bank, Paper for the Conference 2001 of the European Society for the History of Economic Thought
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