Since democracy has already been tackled, I’ll address nationalism head on.

Nationalism is a modern concept with its roots in the 18th century, but in its modern meaning did not come about until the 19th century. Historians are now generally opposed to calling pre-18th century polities “nations” at all, because the word implies a broadly held conception of a shared cultural identity that broadly speaking, we have little evidence for that. Nationalist ideology for most countries says otherwise, but it’s generally not supported by facts. A shared “national” political, social, and cultural identity developed in most European countries only after the French Revolution.

In the ancient world there were certainly people who had fealty to their particular polity, and this is exemplified by the elite discourse that we have from 5th century B.C. Athens and 2nd/1st century B.C. Rome. But we simply have no evidence for a society-wide push for anything resembling a “national identity” with shared culture, ideology, language, etc. There were, perhaps nascent elements of nationalism present in ancient societies, but nothing that rises to the level of the 19th century in Europe.