Suggestions for era tied unit recruitment needed

[Zombimode]

To all the history buffs out there:
I'm currently working on a mod that ties recruitment to proper eras.

I'm in the phase to figure out which units of which factions belong to which era.
I decide it mostly on apearance. If a unit wears equipment appropriate to the era, then its in. If not, its out.
Ie. european city militia wear light chainmail max, so they are available in the early era, but not in the high or late era.

That said, I've problems with the factions of Hungary, Poland and Byzantium.
So, I ask you: which units are appropriate in which eras for these faction, and which not?

Thx

[Darkarbiter]

The long road has a similar feature. The era system is based on armour.