Here are the revised Parthians, thanks to suggestions from @Nordsultan and @Mahazona (economy bonus, unique mechanic, different Imperial tech, etc). The civ is being updated every now and then, shown here. Here’s the current draft, minus the expanded tech tree. Please point out any problems that you see!
PARTHIANS
Cavalry and Trade civilization
Bonuses
- Can upgrade Heavy Cavalry Archers to Imperial Cavalry Archers.
- Trade units can switch between generating wood/food/gold/stone.
- Farmers drop off +10% food.
- Conscription +50% effect.
Unique Units
- Cataphract (Chronicles): Stronger but more expensive version of the Lancer.
Cost: 80 food, 90 gold.
Training time: 30/27 seconds.
Upgrade cost: 1600 food, 1200 gold.
Health: 145/170
Attack: 13/15
Reload time: 2.0
Armor: 2, 3 / 3,4
Speed: 1.4
LoS: 5/6
- Imperial Cavalry Archer: improved Heavy Cavalry Archer.
Changed Statistics:
HP: 75 (+15)
Attack: 8. Bonus: +5 vs Spearmen. (+1, +1)
Reload time: 1.9 (-0.1)
Training time: 25 (-5)
Upgrade cost: 1200 food, 900 gold.
Unique Technologies
CASTLE AGE
- Taxation: Trade units +2/2 armor and generate +20% resources.
- Warhorses: Cataphracts regenerate 20 hp/minute.
IMPERIAL AGE
- Parthian Shot: Cavalry Archers and Galleys +1 range, Cavalry Archers -75% attack delay.
- Kontos: Cataphracts gain a charge attack that gives them +11 damage. The entire strike ignores armor. Charge time: 45 sec.
Team Bonus
- Trade units +2 LoS.
Missing techs: Recurve Bowman, Paragon, Elite Guardsman, Battle Drills, Arson, Lancer, Siege Onager, Heavy Scorpion, Siege Ballista, Chain Mail Armor, Lighthouse, Arrowslits, Siege Engineers, Sappers, Fervor, Sanctity, Illumination, Redemption, Heresy, Block Printing, Atonement, Theocracy, Trireme, Shipwrights, Scoop Nets, Heavy Incendiary Ship, Onager Ship, Hypozomata, Gold Mining, Stone Shaft Mining.
Historical explanations for bonuses
- Farming: the Parthians were located in the Fertile Crescent region, which was known for its agriculture. EDIT: They only controlled the eastern section of the Crescent.
- Trade: the Parthians were smack in the middle of the silk road.
- Conscription: they had almost no standing army not could quickly raise one if needed.
- Military: see the top of this page.
- Navy: no history at all, so I did the bare minimum and made Parthian Shot affect Galleys as a small bonus.