The Edain seem to act as auxiliaries within the Noldor military system, and I think it’s interesting to look at their relationship to the Noldor with comparison to historical auxilary systems. At first the Edain’s main settlement is Estolad, with many Edain moving first in small numbers and then, over 50 years, thousands move into the lands of the Noldor.
Whatever the case, this arrangement is clearly considered unsatisfactory. In the Silmarillion we are told: “After a time the Elf-Kings, seeing that it was not good for Elves and Men to dwell mingled together without order, and that Men needed lords of their own kind, set regions apart where Men could live their own lives, and appointed chieftains to hold these lands freely. They were the allies of the Eldar in war, but marched under their own leaders. Yet many of the Edain had delight in the friendship, and dwelt among them for so long as they had leave; and the young men often took service for a time in the hosts of the kings.”
It seems likely that bigotry and racism played at least some part in the desire to separate the Edain from the Elves, perhaps including fears of the possibility of relationships and marriages between the two. It also isn’t clear where these Men reside, and it doesn’t seem like there was any formal arrangement at this point. It may be that the Noldor’s population density was low enough that they could easily settle the Edain within their lands on new farms and villages, or incorporate Edain families on existing Noldor farms which had too much land and too few hands to work it. We don’t know how effective elven agriculture was, it may be that the Noldor could grow better, more calorie rich food with less labour, allowing for a higher urban population. This would of course leave more land for the Edain.
The change and formalisation of this relationship was driven as well by military concerns. The Noldor need more soldiers to fight Morgoth, and are unable to make good their own losses. The Edain are expected to make up this shortfall, providing new forces, fighting under their own leaders to do it. This would be in addition to topping up existing ones, implied by the line about Men taking service for a time in the host of elven kings. This would also give experience to the Edainic troops in fighting in the same fashion as the Noldor, creating a strong ‘core’ around which to build their own forces, though the Hadorians certainly seem quite militarised to start with. The Noldor’s aim with this relationship is to maximise military potential, they’re not interested in exploiting the Edain for wealth, only for manpower. In that it resembles the Socii system of the Roman republic, whereby cities allied with or conquered by Rome within Italy wouldn’t pay taxes to Rome but were expected to provide troops when asked.
While the Edain who perform this service directly for the Noldor kings may be paid in money, it doesn’t seem like the Edain’s own forces are paid for by the elves. Instead the land is granted to them by the Noldor, and then it is the responsibility of the Edain’s own chieftains to raise military forces when the Noldor require it. This system makes use of an asset, land, that they have in abundance while costing nothing and putting no bureaucratic strain on the Noldor to organise these forces.
This granting of new lands may also make it easier for the Edain to be better armed and equipped. With access to significant, better quality land to produce agricultural surplus that allows them to spend more time and money on armour and weaponry. It may also be that elven blacksmiths were taking Edainic apprentices, and buying weapons from the elves themselves, though even for Húrin an elven knife was a great expense, as we see from the one given as a birthday gift to Túrin.
This all seems similar to another Roman auxiliary system, the Foederati system used by the later Roman and western Roman empires. These were often settled on land within the empire that had been depopulated in war, often wars against peoples who themselves became Foederati once defeated. This system was rife with abuses on the Roman side, resulting in several significant Foederati rebellions. Foederati leaders however did become prominent within the western Roman state, and as its economy declined the western Roman army became increasingly dependent on Foederati forces, with the last western Roman emperor being overthrown in Italy by the Foederati leader Odoacer (who was in turn defeated by Theoderic, King of the Ostrogoths, who had been Foederati of the eastern Roman empire).
Hador gets by far the best deal of all the Edainic chieftains. He gets Dor-Lómin, previously the land of Fingon, Fingolfin’s son and heir. This seems very strange, but Hador holds a pretty strong hand in negotiations. He has the largest force of all the Edain, and the Noldor need that manpower. I do wonder if there was any political fall out from that, between Fingolfin and Fingon. It certainly undermines Fingon's position as Fingolfin's heir. What happened to the Elves already living there? Did they fall under Hador’s authority? Did many stay or did all or most leave, by choice or compulsion? This is complicated of course by the Sindar who live under the rule of Noldor kings, many of whom still have some loyalty to Thingol as King of the Sindar, who at that point at least was certainly no friend of Men.
The Edain obviously have far better relations with the Noldor than the Foederati did, their terms seem to be honoured generally and they remain loyal to the end. The attempt by the Fëanorians to extend this system to the Easterlings goes a lot less well. Perhaps the reputation for treachery established by the kinslaying and the coup in Nargothrond counts heavily against the Fëanorians here, with the people of Uldor rebelling against them and joining the enemy. Perhaps they were settled on low quality lands, Morgoth rewards the Easterlings who side with him with Dor-Lómin, suggesting that whatever lands the Fëanorians gave them were lower quality.
Part of this is definitely just cold calculation. Uldor’s people believe Morgoth will win, and so align themselves with him. This may come from them having more familiarity with him, and a better understanding of his power. It’s notable that Húrin, even after the fourth battle, doesn’t just agree with the Noldor’s cause but has a genuine belief that they will win the war. Morwen of course doesn’t share this belief.
