How did the concept of Nation-States develop in Europe?

During the 19th century, nationalism emerged as a force which brought about sweeping changes in the political and mental world of Europe. The end result of these changes was the emergence of the ‘Nation-State’ in place of the multinational dynastic empires of Europe. The concept and practices of a modem state in which a centralised power exercised sovereign control over a clearly defined territory, had been developing over a long period of time in Europe. But a nation-state was one in which the majority of its citizens and not only its rulers, came to develop a sense of common identity and shared history. This commonness did not exist from time immemorial; it was developed through struggles, through the actions of leaders and the common people.