最小的军事单位被叫作 大队（cohort）。A cohort is comprised of 1000 men; these 1000 men are subtracted from the manpower pool when the cohort is recruited. A number of cohorts can be grouped to form one legion. Any character in the realm can be designated as leader of a legion.
有 9 种陆军单位。
The different unit types are equal in base stats before bonuses from advancements, inventions etc. However, each does have a bonus or penalty to damage against each other unit type, which applies only when it is actually attacking that unit. In addition, some unit types have modifiers to:
- Attrition weight: This increases or decreases the size of a cohort for the purpose of determining whether the army exceeds the supply limit of the city it's in. This does not affect how many units can be transported by sea. But units out at sea, do take attrition!
- Morale damage taken and strength damage taken modify respectively the damage taken to a cohort's morale and strength in combat.
- Requirements: Archers and light infantry can be built by anyone in any owned city, whereas other unit types require either specific traditions or for the province to have a particular trade good.
Some unit types prefer to deploy on the flank; these are light cavalry, camel cavalry, and horse archers. However, the army's selected flank type will take precedence. A unit's maneuver stat determines how far away it can strike in combat; cohorts with higher values are better for flanking.
Only infantry (including archers) can assault fortresses.
The cost and recruitment time of the different cohort types is also important to consider: light infantry has penalties to damage against everything else, but it's also the cheapest type and the quickest to recruit, and can be recruited anywhere regardless of trade goods.
Finally, bear in mind the effectiveness of each unit type for choosing between different combat tactics.