How 19th century European nationalism was everywhere problematic like Ireland

"In linguistically mixed regions delimitation is a thorny problem even where there is mere juxtaposition of national groups. But in Europe intermixture was as a rule the result of past conquests, political and cultural, which had reduced the original national group to a state of social inferiority. Conquests created Ulsters, and over further, wider regions spread the network of an 'ascendancy' primarily based on the landowning classes and the town population, alien to, or alienated from, the peasantry which retained its own language or religion, or both. Self-government meant, in the earlier stages, the rule of the big landowners and their retainers in the countryside, and of the upper middle-class and the intelligentsia in the towns; their language or religion determined the national character of the country (Grattan's Parliament, composed of Anglo-Irish Protestants, deemed itself representative of the Irish nation). Hence in the numerous Irelands scattered all over Europe turmoil and strife were bound to result from the rise of the lower classes, and especially of the peasantry, to political consciousness and action. National and religious conflicts interlocked with agrarian movements, envenoming each other: war was waged for both the national and the personal ownership of the land, and either side felt that it was fighting not for private interests only. An educated upper class, for centuries accustomed to consider the country its own, would not easily allow itself to be reduced to the position of alien interlopers, while peasants rooted in the land, as only they can be, fought the long-drawn battle with an obstinacy unsurpassed by any other class. Moreover the dominant minority invariably had the backing of its Ulster and of its homeland: even under democracy. With the progressive widening of the political nation, the unprivileged orders, one by one down the social scale, were taking over the quasi-proprietary claims of dynasties and feudal oligarchies to territorial dominance; they became ideological partners or heirs of their quondam rulers, and frequently their actual partners by being settled on the land or in government posts in the disputed territory. Peasant-settlers planted as a garrison to keep down the subject race, school-teachers sent to spread the language of the minority, and a host of petty officials, constituted a master-nation whose rule was much harder to bear, and more galling, than that of a dynasty or of a remote oligarchy. Consider the amount of disturbance which during the nineteenth century was caused in the political life of this country by an Ireland geographically isolated and not subjected to any further encroachments; and you can gauge the effect which two dozen Irelands were bound to have on the life of nineteenth-century Europe as borderlands between contending nations, especially while attempts continued to be made to complete conquest and conversion."

("Vanished Supremacies", by Lewis Namier, pp.166-167)