Частично (кратко) резюме на темата:  

In my opinion this statement-“Nations have always existed”-is not true. There are several stages of the human evolution until the word “nation” appears as a term. In fact these stages are three - ethnos, nationality and nation. “Nation” is the last level of social development. My thesis is based on historical evidences and views of famous historians. The conclusion I made, after getting acquainted with some sources, is that nations have developed during the XVth or XVIth century, more precisely after the Great French Bourgeois Revolution in 1789.
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