I suggest looking at our own world's history. For example, the "Hundred Years' War" and the "Thirty Years' War". And the army numbers you citd look very large, so I suggest finding one of the several Web sites devoted to helping this area of fantasy worldbuilding be more plausible. (Like this one.)

Yeah, it reminded me of the 100 Year's War. They'd need time replenish supplies, repair weapons, for injuries to heal, time to work out logistics, and time to farm.

An army of 5,000 men is certainly not "very large."

Bill Potter would be an excellent resource for anyone wanting to research warfare, weapons, strategies, and the likes. He's not only an expert; he's a historically accurate one.

I love his series Sabers, Spears, and Catapults.

He talks about war lengths at one point.

No problem. Providential Battles is by him, and very good. You could start there.

I know you will enjoy it.

The ability to sustain vast armies is based partly on economics, yes, but also partly on infrastructure. Infrastructure effects the quality of goods, ability to move goods, ability to acquire goods, ability to reimburse soldiers, etc.

An entire nation of shepherds is probably doomed going up against a single, but powerful, city state, if that city state has good infrastructure. (This is, incidentally, the reason city-states were the primary power-houses of ancient times, rather than populous rural areas.)

Rome conquered because it had a good infrastructure.

It fell, not because it had a bad economy, but because its conquests extended well beyond its infrastructure's area of support.

Infrastructure also effects your ability to continue a war, for say, 50+ years. As long as you are careful to maintain your infrastructure, you could pursue a war for nearly indefinitely, as long as you have a somewhat significant population base.

Thanks for your input Neil!

Infrastructure... I'm guessing that means the ...um. The way they move resources/manpower around? The way they manage themselves?

...but infrastructure advances are not a cure-all.

Agreed. I wasn't trying to say that wars are won and lost on infrastructure.

What I was trying to say is that infrastructure is a primary factor in war length. Resources (people, as well as nature), the other primary factor in war length, can either be wasted or increased by infrastructure. Which makes infrastructure a controlling factor over resources.

Compare Alexander the Great's Greece to the Roman Empire. Alexander the Great conquered nearly as much a Rome, but his empire had zero infrastructure. Most people contribute the collapse of that empire to the power vacuum left after Alexander died, but the truth is that if the empire had been united by a solid infrastructure, a cunning leader could have taken over after Alexander and kept most of the empire.

Rome, on the other hand, maintained a vast Empire for years upon years, thanks in large part to the infrastructure. Rome was able to basically remain at war for the larger part of a century, because of infrastructure.

A suggestion for you, Wolf. In some of the missionary biographies I've read, people find these remote tribes engaged in a endless cycle of killing. If a family member is murdered, then someone from the opposing party must be killed in recompense, which leads to some being killed in recompense, which leads too....

I think you get the idea. Anyway, that's one way to keep a feud brewing, theoretically forever.

Infrastructure is defined as "basic organization" and "public services or systems". So yes, it is the way you move stuff around, and how you manage moving stuff around. So, for example, you need both good roads, and good shipping managers. But it's more than roads: it's also dams, waterways...anything that...moves stuff. And moves stuff efficiently. Horses, for example, will pull a carriage faster than, say, a turtle.

Hasn't Ireland been at war for hundreds of years now?

Isn't trench war also classified as little advancement on either side, but heavy casualties?