Why was there a need to move from the rule of dynasties to nationalism?

Explanation:

Nationalism holds that each nation should govern itself, free from outside interference (self-determination), that a nation is a natural and ideal basis for a polity and that the nation is the only rightful source of political power (popular sovereignty).

the story goes that because of this belief, constantine was able to defeat his foes. constantine became an ardent1 christian. christianity and other religions were tolerated under constantine's rule. constantine also was responsible for the building of a great cathedral in rome.

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