Writing in 1751, Voltaire described Europe as 'a kind of great republic, divided into several states, some monarchical, the others mixed ... but all corresponding with one another. They all have the same religious foundation, even if divided into several confessions. They all have the same principles of public law and politics, unknown in other parts of the world.'
Ten years ago, this January 1, in a way that Charlemagne, Voltaire, William Penn and Gladstone, the early advocates of European unity, could only dream, a united Europe became a reality. A single currency was the most dramatic step taken towards what surely one day will be a single political entity.
War, time and time again, has interrupted the pursuit of that objective. Continued civil war across the continent, across the centuries, reached its dreadful climax in the second world war.
The fact that the urge to bury the hatchet and forge common institutions has come so far in such a short time against such a background is arguably the 20th century's greatest political achievement.
Yet this triumphal moment begs the question, what is the glue that holds it all together? After all, what is Europe? Geographically, it is a peninsula protruding from the land mass of Asia. Culturally, it has always been a potage of languages, peoples and traditions. Politically, it is a moveable feast.
Indeed it is religion, not politics or economic and monetary union, that, through the ages, has made Europe one, and provided the common morality and identity that make a single currency possible today and political union a tangible, if still hotly debated, goal tomorrow.