We're going to start at the beginning – 48. Not 1948, 1648. I'm not kidding. In 1648, the Treaty of Westphalia was signed. This was the treaty that ended the 30 years war between . . .

Wait.

We have to back up even further.

To – the medieval period, Europe. There were many different authorities competing for control and loyalty of the people – monarchs, priests, nobility. The European landscape was just starting to be partitioned into 'states' controlled by central authorities. The powers of these governments were expanding rapidly. Local authority declined, central authority increased. As you might expect, the scale of political conflicts also grew during this time. And so, military technology advanced with the development of guns and artillery, which made warfare more expensive. In order to make – and pay for – these new war tools, monarchs, priests, nobility (whoever was in charge) needed to control large territories of land with a sufficient number of tax-payers and adequate urban development.

The big fight going on was between the Catholic Church/Roman Empire on one hand, and the emerging territorial kings and queens on the other. Both wanted to be the ones in control. This led to the 30 years war – it involved most of the major European powers at the time. It started as Catholic vs. Protestant, but what was really at stake was imperial sovereignty – not God. It ended with the Treaty of Westphalia – many historians mark this treaty as the start of the modern era.

Why?

First, it set up the inter-state dynamics that we've been seeing play out over the last four centuries. Second, it broke up the Holy Roman Empire. This ended the legitimacy of the Holy Roman Empire's secular dominion over the entire Christian world. Now the state would be the highest level of government, subservient to no others (i.e. not any church). The relationship of subjects to their rulers changed. Before, people had overlapping political and religious loyalties – and they could play one against the other. Now, the state was the highest power. All other loyalties, laws, and legal systems came second, third, fourth.

Fast forward a few centuries. In 1815, with the Congress of Vienna (the end of the war between France and everyone else), the political map of Europe was, well, drawn. Before this point, boundaries of states were still pretty blurry. In 1815 came the rise of the modern state – a territorially unbroken area with defined borders, governed by a single authority and a system of administration. Just think about that for a second.

States as we know them are only 2 centuries old.

These new territorial states led to the even more modern concept of "nation-states." And boy did this idea catch on . . .