One thing I sort of wished was touched on a little more: the concept of country is surprisingly modern. Modern international relations theory tends to trace the concept back to the Peace of Westphalia in 1648, but honestly, even that is really too early.
The map shown of 14th century Europe is doing better than most in that recognizes that several borders (but still too few) are fuzzy rather than lines on a map. The other problem you run into is that, in most non-state societies (in the Weberian sense of "monopoly on the legitimate use of force"), political linkages tend to be fragile and based more on personal ties so that a Big Man's successor may well repudiate the alliances and homages the Big Man makes. Which makes it hard to draw maps, because is Burgundy a part of France? The Duke of Burgundy is as often as not fighting the French king.
This is what makes adjudicating the "oldest continuous republic" hard, because at what point do we say that the homages San Marino is paying stops counting as being part of that country?
You also have three distinct concepts:
– country (geographically defined territory with something binding it)
– state (political entity with sovereign authority over a territory)
– nation-state (a state in which most people share some common identity)
Yeah, this is sometimes really interesting. For eg Scotland, Wales, NI and England are technically all different countries. Just like Aruba (and other Carribbean/island micro nations) which technically is still in the Kingdom of the Netherlands.
Games like EU4 do have multiple views of the map for this reason. There are so many ways you can subdivide and draw borders differently. Language, culture, religion, imperial, etc.
Westphalia did two big things in my view… 1. is permanent diplomacy and 2. it made sure that things were on a secular not papal foundation. It’s a big deal but to claim that countries weren’t a thing before it is a bit of an overstatement.