The rhetoric of “Europe” in its recognizably modern form dates back to the Thirty Years’ War. After all that they had done to each other between 1618 and 1648, Europeans were rightly embarrassed to talk of “Christendom” as a serious political concept. The last mention of a Christian commonwealth was made in the Peace of Utrecht in 1713.
“Europe,” said Czar Alexander I a century later, “is us”—by which he meant the political decisionmakers at the Congress of Vienna. His view of Europe as an informal association of like-minded leaders who accept one another’s legitimacy in the intricate act of power-balancing was the cornerstone of the post-Napoleonic Concert of Europe and of the Long Peace that lasted from 1815 until 1914.
The tendency to try to create “European” cultural commonalities as a substitute for the old, Christian ones is also not new: The notion of a “European” community was hugely appealing to the philosophes. Writing in 1751, Voltaire was enthusiastic in his depiction of Europe as “a kind of great republic.”
“Today, no matter what people may say, there are no longer any Frenchmen, Germans, Spaniards, or even Englishmen; there are only Europeans,” wrote Rousseau two decades later.
If those who run the institutions of...