- +10 Metal gather rate
- +10 Knowledge gather rate
- Foot Archers, Ranged Cavalry, Towers, Forts and Cities gain +1 attack strength
The gather rate of rare resources can be increased in various ways, as described in the main article. Note that Metal and Knowledge is not gathered until a nation has entered the Classical Age (except for the Greeks who can gather Knowledge at start) and linking a Obsidian resource while still in the Ancient Age might not provide the full benefit.