Age of Empires
Chain Mail

Age: Iron

Prerequisites: First build a Town Center, then build a Storage Pit, research Leather Armor, research Scale Armor.

Cost: Infantry: 125 Food, 100 Gold
Archer: 150 Food, 100 Gold
Cavalry: 175 Food, 100 Gold

Benefit: Chain Mail for Archers = +2 armor for Archery Range Units
Chain Mail for Infantry = +2 armor for Barracks and Academy Units.
Chain Mail for Cavalry = +2 armor for Stable Units.

Research At: Storage Pit

Must research Chain Mail for Archers before you can upgrade to Heavy Horse Archer