How'd they do it?

[Griever14206]

It seems that following the fall of the Roman Empire, instead of the world containing 5-6 superpowers (as it did around 240 BC) many of the "nations" that participated in organized warfare were very small, and therefore the sheer volume of their armies would be reduced. Most of Europe was of course in the Dark Ages, which meant that civilization was on the down-low, which of course meant that means of producing goods was in decline, and therefore the ability to produce arms and armor was also lessened to a great extent.

One must also consider lack of any record keeping whatsoever, and therefore it would be difficult to keep track of how many people you governed, making summoning such people to fight extremely difficult.

Edited for coherence.