Armor Bonus is a decrease in the amount of damage a unit takes from attacks of the matching type. It is a part of the battle equation. Damage incoming from an attacking unit of the specific type is divided by this number.
- Pierce Armor: Reduces Pierce damage, primarily dealt by ranged Attacks by Ranged units, Ships and Buildings
- Melee-Infantry Armor: Reduces Melee-Infantry damage, primarily dealt by Infantry units in close quarters combat (Throwing Axemen still deal this damage at range, while Infantry units who can attack at range have a secondary attack with Pierce attributes)
- Melee-Cavalry Armor: Reduces Melee-Cavalry damage, primarily dealt by Cavalry units in close quarters combat (Sarissophoroi deal Pierce damage despite counting as Cavalry, while any other mounted unit with a ranged attack count as Ranged entirely)
- Crush Armor: Reduces Crush Damage, primarily dealt by Siege units. both at range and in melee (though Battering Rams can only attack buildings in the first place)
- Bonus Damage Protection: Extra damage reduction that only applies to damage from units with Bonus damage against the target
- Splash Damage Protection: Extra damage reduction that only applies when the attack has a Damage Area property, like most ranged Siege units and the Fortress.