Abilities and influences
Attack Drums
Mehter drums that increase the attack speed of nearby units by +15%. Toggle on 
Mehter Speed Bonus
Units move +15% faster when in formation. When in 6 tiles range of
Melee Defense Drums
Mehter drums that increase the melee armor of nearby units by +2. Toggle on
Ranged Defense Drums
Mehter drums that increase the ranged armor of nearby units by +1. Toggle on
Blacksmith and University Influence
Military unit production rate increased +20%/+30%/+40% by Age while within the influence of a Blacksmith or University. The Istanbul Observatory increases the bonus to +100%.
Produced at
Technology Upgrades
Angled Surfaces
Age IVRanged Armor Technology 3/3
Increase the ranged armor of all non-siege units by +1.
Balanced Projectiles
Age IIIRanged Damage Technology 2/3
Increase the ranged damage of all arrows and bolts by +1.
Biology
Age IVLancer Technology
Investing in natural sciences increases the health of all cavalry by +25%.
Fitted Leatherwork
Age IIMelee Armor Technology 1/3
Increase the melee armor of all non-siege units by +1.
Insulated Helm
Age IIIMelee Armor Technology 2/3
Increase the melee armor of all non-siege units by +1.
Iron Undermesh
Age IIRanged Armor Technology 1/3
Increase the ranged armor of all non-siege units by +1.
Master Smiths
Age IVMelee Armor Technology 3/3
Increase the melee armor of all non-siege units by +1.
Platecutter Point
Age IVRanged Damage Technology 3/3
Increase the ranged damage of all arrows and bolts by +1.
Steeled Arrow
Age IIRanged Damage Technology 1/3
Increase the ranged damage of all arrows and bolts by +1.
Wedge Rivets
Age IIIRanged Armor Technology 2/3
Increase the ranged armor of all non-siege units by +1.