Italy, unified in 1870, is newer than Nevada. Spain was split down the middle by a civil war as recently as the 1930s. And reunited Germany, dating back only to 1990, is younger than two of the Jonas Brothers. Just a reminder that, for all their claims to antiquity, many of the nations of Europe have been nations for only the briefest of times. For most of history they were rivalrous territories, kingdoms, duchies, principalities, and city-states. They were bound by language and culture—and riven by tribalism.