Loyalty by the commoners/peasants/plebeians towards the rulers/kings(queens) of the lands actually did exist back in medieval times .. it was just binary and dependant on the state of the neighbouring regions.
If the ruler treated his/her subjects well(enough), and kept tyrannical neighbouring rulers from invading/pillaging the "countryside", then they would help defend the land(although quite begrudgingly).
But that loyalty was fickle as soon as a "better" ruler came invading and there was a hint of a better life under him/her(preferably to just be left alone).
On another note; Nationalism is nothing more than Tribalism on a much larger scale, so technically Nationalism DID exist back then .. there just wasn't much of a sense of common culture/history with those a weeks travel away...
Tribalism is actually *before* Feudalism. It is also before nations as we presently understand it. To my reading of history Tribalism (society economically based upon extended kinship) comes before Feudalism (society economically based upon individual households) and the nation is really the invention of (later) Feudalism in an attempt to overcome Tribalism by substitution. The Nation is *not* the continuation of the Tribe, the Nation is the psychological substitution for the Tribe.
The transition between Tribalism and Feudalism happens at various points in time depending upon where you are. The Romans are the main protagonist in this transition, they were the main force that destroyed the old tribal order and as a result in places where they failed to conquer (Poland, Scotland, Ireland, Scandinavia) tribal/clan arrangements remain a major power in the middle ages, contrasting to the places (like England) where they did conquer. This is in turn complicated somewhat by how the Roman Empire was overthrow by German tribes, so we see some backsliding but thanks to the inability of the conquerors to entirely turn the clock back socially in places the Romans conquered we end up with what most people think of as Feudalism during the middle ages (except in Poland, Ireland and Scotland mostly).
Here is the confusing part, the role of city-states, like Ancient Athens. Athenian citizenship was purely tribal, normally in order to become a citizen you had to be born to both an Athenian mother and a father, it was not enough to live in Athens and speak Greek. But the economy was more Feudal, Athens economic unit is mostly that of the household, but the political system renounces the importance of household for that of the extended family kinship. In effect these are semi-stable compromises between the conflicting systems of Tribalism and Feudalism; weakened by their internal contradictions. As a result these systems are then swept away by the more stable purely Feudal systems of Macedon and Rome.
The Macedonian system is pretty much identical to medieval Feudalism so does not require much discussion. The Roman system is, while superficially similar to that of the Greeks actually not so because the basis of the Roman political system was the nuclear family. Rome was not built on the assumption that Rome is a single extended family that grows outward from it's collective ancestors but is understood as a union of originally independent nuclear families, a union that gradually grows over time as new families are (slowly) admitted and citizenship is thus extended. In this fashion the Roman Empire atomized the tribes of Europe and the semi-tribal cities like Athens down into their nuclear families through extreme violence, before *eventually* gobbling up those families into Rome so that by the time it's collapse everyone was a Roman citizen.
This is the problem the Romans run into. At the time they are around Nationalism is very weak, if it exists at all. People are 'Nationalistic' about their tribes, or their cities which are often the same thing as already discussed. Over the course of their empire however the Romans successfully annihilate those things, but they leave a vacuum because the loyalty of the Romans is to Rome not to a nation. Not being a nation they cannot truly absorb the de-nationalised elements through the process of extending them citizenship and the end result is a situation where small numbers of people can conquer the place with ease because nobody is prepared to die for it.
The fundamental problem is how to bind a society based upon atomized nuclear family households, which unlike tribal arrangements are very vulnerable to attack (hence Vikings) together into territorial units of sufficient scale that they can afford to mobilize sufficient forces to keep small numbers of raiders at bay and to give those forces something they will die for. This is a form of warfare between the Tribal and Feudal systems, the Vikings are a Tribal society while their victims are Feudal. The Viking problem would be solved by a return to Tribalism but that was not ideologically acceptable to people inspired by Rome. So that is why we end up with Nationalism, in order to not abandon their Feudal society and return to a Tribal one for the sake of security they have to create Nation-States in order to secure their fundamentally insecure way of life and they ideologically need to promote loyalty to such concepts.
GC I highly recommend The Prince and Discorsi by machiavelli. Just because you didn't have to bribe the population doesn't mean that it wasn't smart to do so anyway. The leader highly depended on the loyalty and fear of its subject
I've read the Prince before, but not not the Discourses. I was the one arguing that the loyalty of the subjects was important, Cathar was the one arguing the opposite, that the ordinary folks had no loyalty to their leaders. In any case however, the key claim he was making was that nationalism did not exist back then, I was arguing it did. The Prince speaks of the difficulty of ruling over conquered lands and proposes as one solution that the ruler 'take up residence' in the conquered land; which is pretty much advising that he 'emigrate' to become visibly part of the foreign nation. Without Nationalism however, ruling over conquered foreign lands would be no different from ruling over your native lands.