The Imperial Civilization

Dark Age: Can train Pilgrims and create Monasteries at this age, Pilgrims are similar to Monks.
Feudal Age: Monasteries gain 200% HP, Spearmen gain +3 Attack
Castle Age: Pilgrims gain +5 Healing Range, and gain 150% more passive gold from buildings
Imperial Age: Spearmen and Skirmishers gain +6 LOS and train 35% faster, gain 250% more passive gold from buildings

Synergy Bonus: per age : Imperial Age costs 25% less resources to research

Team Bonus: Pilgrims and Monks gain +5 Healing Range

Castle Exclusives :

*Greekfire : Fireships move 45% faster and gain +2 Range
*Logistica : Cataphracts gain 0.75 splash radius, and deal +18 damage vs. Infantry
*Emperor's Trident : Spearmen gain +1 Range, +135% HP, and train faster equal to synergy %. (so 100% at Imperial Age)