Nationhood is in part primordial (deriving from attachments to group and homeland that evolved in prehistory); some nations are perennial (in that they arose in medieval times and have a long continuous existence); and nationalism is also modern in that it has spread like wildfire in modern times.
This is true of other things.
The system of states is primordial in as much as people have always been divided into separate groups; perennial in that there is a long continuity stretching from the medieval European multistate system to today’s; and modern in that it has been reshaped by the winds of modernity.
Civilizations are also in part primordial (arising from the divergent populations that evolved in prehistory), but also perennial (today’s civilizations arose in antiquity), but also modern (for modernity has brought great changes to all civilizations).
In these ways, prehistory matters, ancient history matters, and modern history matters.