1. Socio-economic factors – Industrial Revolution
2. Cultural factors – Nationalism
3. Political military factors – War


Socio-economic factors

As we have seen, the Industrial Revolution transformed the economic basis of society with enormous social consequences. The old ruling classes, the great land-owners were under pressure from the new rising middle classes – the industrialists – to reorganise the country politically. Giving the industrialists a say in how the country was run, would allow them to reorganise the country in the interests of industry. This meant encouraging free trade, allowing the free movement of people and ending feudal obligations and ties. It meant in brief, liberalism. In much of Europe, people were often either under the feudal control of small feudal states (as in Germany) or the feudal control of foreign empires (such as the Austrian Hapsburgs or Russian Romanovs).
 

Either way, if capitalism was to develop, these inefficient economic systems would have to change. As Marx and Engels argued:

‘The necessary consequence of this was political centralisation. Independent, or but loosely connected provinces, with separate interests, laws, governments, and systems of taxation, became lumped together into one nation, with one government, one code of laws, one national class-interest, one frontier, and one customs-tariff.’ Karl Marx and Friedrich Engels: The Communist Manifesto (1848)
 

Cultural factors

And of course the development of industrial capitalism not only required the creation of nation states, capitalism also made it possible. By the late 19th century, subjects of monarch had become citizens with a democratic stake in the future direction of society. Individuals had lost their traditional peasant attachments and village loyalties as they were urbanised, educated and introduced to the ‘imagined communities’ and ‘invented traditions’ of the new nation states. They read their daily national newspapers in codified national languages, attended new schools with state directed national curricula, travelled across their nation on national railway networks and went to war waving newly invented flags (see Johnson's chart below from 1867), singing newly composed anthems.

In a time when the church and feudal ties were being weakened, nationalism, as the German philosopher Hegel pointed out, was a useful way giving people a sense of belonging and something to be loyal to. Nationalism became the cultural glue that bound society together.

Where the nation states did not yet exist, nationalists set out to create them. Popular movements like Young Italy and Young Ireland, inspired by Romantic philosophy and literature, established the principal characteristic features of the nation and campaigned politically for its creation. Romanticism was a reaction to the Enlightenment that emphasised not human rationalism, but rather human emotion. Romantic artists and poets contrasted the beauty of wild nature to the ugliness of the new cities. Romanticism and nationalism shared a longing for an idealised past.