Please bear with me as I'm actually having a hard time wording my question, such is my ignorance and ill-equippedness in the subject.
So as I understand, the concept of the 'state' (i.e. what we colloquially call a 'country') really came into its own after the Peace of Westphalia. Before that, territorial boundaries were not really respected by rival monarchs, and so no true concept of a sovereign state existed.
Then the idea of 'nation-states' came along, wherein states where defined and empowered by the nation (i.e. the people, or ethnoliguistic group) that were its population. Not quite sure about the boundary there (i.e. when is a state not a 'nation' state?)
So I'm trying to figure out what came before.
Before the concept of states, how did people really organize the world?
From how I understand it, there was the concept of 'realms', i.e. areas wherein a magnate or monarch held power (god-mandated sovereignty).
But was a realm defined as the entire territory (and all the resources within, such as the population) ruled by a monarch? Or was there still nationhood built into it, and therefore a realm gained its own identity on its own?
I ask because I've recently been reading up on Phillip II. Now, over the course of his life, from birth onwards, he accrued multiple titles such as King of multiple 'states'. He was King of Spain, King of Portugal, King of Naples and Sicily, King of England and Ireland*, Duke of Milan and lord of the Seventeen Provinces of the Netherlands.
How did that work? Were all of those territories considered a single, aggregate 'realm'? I.e. a single territory under his rule? If so, what was the word and concept used to define 'Spain', 'Portugal', etc.?
If each those were considered realms (i.e. kingdoms) in their own right, then how was each kingdom defined? If they were defined as 'the territory ruled by a king', then wouldn't they be 'assimilated' into the larger 'realm' of 'Phillip's State'?
Or am I approaching this wrong, and kingdoms/realms/states were not defined by who ruled them, but by some other metric or set of rules? That England was a state/kingdom, and acknowledged as such, whether it was ruled by its own King, or was just part of a laundry-list of kingdoms ruled a dynasty? That the territory and its people was a concept that stood inalienable (i.e. similar to a nation), and had its own identity so difficult to extinguish that a dynast didn't just absorb the territory into his realm, but considered it another realm that he ruled in a separate capacity?
Basically, I'm just trying to wrap my head around how society was divided in the past. If it was a top-down system or a bottom-up system of defining each 'territory'.
Any learned input would be appreciated.
Not a historian but have studied political science so will try to give brief input based on that.
Yes the nation-state concept was an experimental Enlightenment ideal, under which international relations continue to be organized to this day, although it is increasingly under strain and may not survive or may evolve into something new.
Before the nation state ideal, a territory may have had certain unifying ethnic characteristics, but those were not considered necessary to governance or rule, other than practical considerations of language, taxation, religion, and such.
Inherent in the nation state concept is the idea that the government takes it's legitimacy from the consent of the nation (the people). Prior to the concept, the consent of the people was not considered necessary for the legitimacy of the government. That feels a bit astounding today but cannot be overstated.
A foreign ruler may have chosen to honor historical practices in a region that comes under his control. Or he may just as well not. Depending on his motives and goals, he may leave a region largely alone except to collect taxes, or he may become extremely involved in language, church governance, birth and death rolls, administration, military draft, education, and the courts.
Consider England after William the Conqueror in 1099. He came in and swept the slate clean, instituting new regimes in all those areas and then some, especially language, real estate, and the courts. This was difficult for several hundred years but over time, the language, customs, and legal practices metabolized the new protocols.
You hardly ever hear of or consider England as being 'under colonization by the French' in that time period. Partly because the culture and legal practices metabolized, but also because the idea of 'colonization' is one of nation-state and empire, which was not the ideological framework of the people of the time.
Today, the nation state ideal is under strain by 'non state actors.' Which sounds like some weird, fancy government speak except it actually has meaning.
The nation-state ideal holds that a nation should be a self-determing group of people who voluntarily give their consent to form a state, and the state then holds a monopoly on violence. Conversely a state is formed of a self-determining nation. But what happens when you have a self-determining nation (ex: ISIS, the Palestinians, the Kurds) without a state? And further what happens if these stateless nations have power via military influence or force? They undermine the very framework of state monopoly on violence, and therefore the stability of international order as a whole.
Historically stateless nations were like the Jewish people, pre-Israel, or like Gypsy/Travelers today, or even like Native Americans/First Nations in the US and Canada. They could be satisfied or dissatisfied with their lot under the rule of other regimes, but they did not have recourse to organized military violence. Only the states had the capital and the wherewithal to produce organized violence. Stateless nations certainly existed, and may have been put down or kept down, but by and large they were not an objective threat to the facts on the ground of day to day governance.
Today, these non-state actors have power the nation-state framework literally is not organized to deal with. It's not 'international terrorism' that is the problem. It is the power of stateless nations to wage war on states, leaving states with almost no recourse to reach them.
Hence, the now global, never ending 'war on terror.' It is an existential war being fought at the root level of the ideological framework organizing the world itself.
It is akin to the violent reorganization Europe went thru in the Reformation and for hundreds of years after, wherein Catholics were under suspicion of being what today we would call international terrorists, because they were believed to answer to the Vatican and not to their local governments. That took several hundred years and great loss of life to play out, and only finally resolved when State was separated from Church - when the ideological framework itself changed. The ancient and dying framework of Holy Roman Empire gave it's last gasps and finally expired. Separation of church and state is taken for granted today (in the west).
What the new answers or solutions will look like in the current and coming upheavals remains to be seen, but the international nation-state framework itself will be changed in some core existential way, if it survives at all.