The most common form of theories on nations and nationalism are based around modernity. Theorists of this ilk are referred to as using modernist or developmentalist approaches. The premise of the modernist theory is that nations have occurred as a natural result of modernity. There is not a specific date belonging to this theory as the key features often listed as the cause of modernity differ from nation to nation. One of the foremost thinkers of modernism and nationalism was Ernest Gellner.

Gellner listed three main elements essential in the building of nations coming from modernity and, more specifically in his theory, industrialisation. Gellner believed that to make a nation, first a centralisation of power was required.  In many cases as industrialisation came about people went from small villages and agrarian areas to bigger cities; thus having a need for more far reaching uniformity in governance and leadership.

This stage in nation building can be seen in the Unification of Italy. Where the provinces and states were once separate and had their own laws and customs, as each state became part of the growing Italian Kingdom so the power would be taken from the individual states, often forcibly removing authority from a foreign power, and made part of the larger collection of states that would one day