With the dissolution of the Roman Empire, Europe was free to develop according to different patterns, based on local conditions. Those parts of Europe that had been under Roman control were to a great degree cured of local divisions that would prevent unification, and thus, nation-states were able to form that encompassed people of a common language or cultural background for the most part. There were however also sections of Europe that had not been under imperial control, and these had to work out their development along somewhat different lines. Sri Aurobindo reviews several of these paths to nation-state status following the fall of Rome:
“The old clan-nation perished, except in countries like Ireland and Northern and Western Scotland which had not undergone the Roman pressure, and there it was as fatal to unification as the city state in Italy; it prevented Ireland from evolving an organised unity and the Highland Celts from amalgamating with the Anglo-Celtic Scotch nation until the yoke of England passed over them and did what the Roman rule would have done if it had not been stayed in its expansion by the Grampians and the Irish seas. In the rest of Western Europe, the work done by the Roman rule was so sound that even the domination of the Western countries by the tribal nations of Germany failed to revive the old strongly marked and obstinately separative clan-nation. It created in its stead the regional kingdoms of Germany and the feudal and provincial divisions of France and Spain; but it was only in Germany, which like Ireland and the Scotch highlands had not endured the Roman yoke, that this regional life proved a serious obstacle to unification.”
France eventually united while preserving the rich cultural variations of the regions. “But in England the necessary variation and richness of the ultimate organism was otherwise provided for by the great difference of the races that formed the new nation and by the persistence of Wales, Ireland and Scotland as separate cultural units with a subordinate self-consciousness of their own in the larger unity.”
Sri Aurobindo, The Ideal of Human Unity, Part One, Chapter 12, The Ancient Cycle of Prenational Empire-Building–The Modern Cycle of Nation-Building, pp. 100-101
Sri Aurobindo Studies 