Building lines
Most lines upgrade as the city's culture level rises; the Hamlet line develops on its own after a set number of turns. Names link to the full details below.
| Line |  Weak |  Developing |  Strong |  Legendary |
|---|---|---|---|---|
| Barracks |  Barracks +20%  +20% Adjacent Garrison +10 XP for Melee Units | — | — | — |
| Baths | — |  Heated Baths 4  +10%  | ||
| Courthouse | — |  Courthouse +20%  |  Ministry +30% |  Palace +40% -10%  |
| Garrison |  Garrison 0.5  +30% Defense in Friendly Territory |  Stronghold 0.5 +40% Defense in Friendly Territory |  Citadel 0.5 +50% Defense in Friendly Territory -10% | — |
| Hamlet |  Hamlet 10  10 on trade network | — | — | — |
| Library | — |  Library +10%  |  Academy +20% |  University +10% +30% |
| Market |  Market +30% |  Grocer +40% |  Fair +50% | — |
| Odeon |  Odeon 3  |  Theater 4 1 |  Amphitheater 5 2 | — |
| Pillar Edicts |  Pillar Edict 2 2  | — | — | — |
| Range |  Range +20% +20% Adjacent Garrison +10 XP for Ranged Units | — | — | — |
| Slums |
↓ develops after 15–35 turns into Hamlet | — | — | — |
| Improvement | Tech | Other Prereq | Cost | Build | Upkeep | Specialist Slot | Effects | Terrain | Restrictions |
|---|---|---|---|---|---|---|---|---|---|
| Garrison Garrison | — | — | 60  1 | 4 turns | 2 /turn | — | 0.5 +30% Defense in Friendly Territory | Habitable Land | Urban tile only Requires 1 active Law Max 1/City |
| Stronghold Garrison | — | Developing | 80 1 | 5 turns | 3 /turn | — | 0.5 +40% Defense in Friendly Territory | Habitable Land | Urban tile only Requires 4 active Laws Max 1/City |
| Citadel Garrison | — | Strong | 100 1 | 6 turns | 4 /turn | — | 0.5 +50% Defense in Friendly Territory -10% | Habitable Land | Urban tile only Requires 7 active Laws Max 1/City |
| Pillar Edict Pillar Edicts · Empires of the Indus | — | Stupa in city | 10 1 | 1 turn | — | — | 2 2 | Habitable Land | Urban tile only Max 1/City |
 Slums Slums · Behind the Throne | — | — | — | not built | 1  /turn | — | -40% Militia Production Time +5% Rebel Chance 5 on trade network | Habitable Land | Urban tile only
Develops into Hamlet after 15–35 turns |
| Odeon Odeon |  Drama | — | 40 1 | 4 turns | 2 /turn |  Apprentice Poet | 3 | Habitable Land | Urban tile only Max 1/City |
| Theater Odeon | Drama | Developing | 60 1 | 5 turns | 3 /turn | Master Poet | 4 1 | Habitable Land | Urban tile only Max 1/City |
| Amphitheater Odeon | Drama | Strong | 80 1 | 6 turns | 4 /turn | Elder Poet | 5 2 | Habitable Land | Urban tile only Max 1/City |
| Hamlet Hamlet |  Polis | — | 20 1 | 4 turns | 1 /turn | — | 10 10 on trade network | Habitable Land | Urban tile only
Develops into Village after 20 turns |
 Village Hamlet | Polis |
Develops from Hamlet after 20 turns | — | not built | 2 /turn | — | 15 15 on trade network | Habitable Land | Urban tile only
Develops into Town after 20 turns |
 Town Hamlet | Polis |
Develops from Village after 20 turns | — | not built | 3 /turn | — | 1 20 +10% Defense in Friendly Territory 20 on trade network | Habitable Land | Urban tile only |
| Barracks Barracks |  Military Drill | — | 40 1 | 4 turns | 2  /turn |  Apprentice Officer | +20% +20% Adjacent Garrison +10 XP for Melee Units | Habitable Land | Urban tile only Max 2/City |
| Market Market |  Coinage | Weak | 60  1 | 4 turns | — |  Apprentice Shopkeeper | +30% | Habitable Land | Urban tile only Max 1/City |
| Grocer Market | Coinage | Developing | 80 1 | 5 turns | — | Master Shopkeeper | +40% | Habitable Land | Urban tile only Max 1/City |
| Fair Market | Coinage | Strong | 100 1 | 6 turns | — | Elder Shopkeeper | +50% | Habitable Land | Urban tile only Max 1/City |
| Courthouse Courthouse |  Citizenship | Developing | 80 1 | 4 turns | 2 /turn |  Apprentice Scribe | +20% | Habitable Land | Urban tile only Max 1/City |
| Ministry Courthouse | Citizenship | Strong | 100 1 | 5 turns | 3 /turn | Master Scribe | +30% | Habitable Land | Urban tile only Max 1/City |
| Palace Courthouse | Citizenship | Legendary | 120 1 | 6 turns | 4 /turn | Elder Scribe | +40% -10% | Habitable Land | Urban tile only Max 1/City |
| Range Range |  Composite Bow | — | 40 1 | 4 turns | 2 /turn | Apprentice Officer | +20% +20% Adjacent Garrison +10 XP for Ranged Units | Habitable Land | Urban tile only Max 2/City |
| Library Library |  Scholarship | Developing | 80 1 | 4 turns | 2 /turn |  Apprentice Philosopher | +10% | Habitable Land | Urban tile only Max 1/City |
| Academy Library | Scholarship | Strong | 100 1 | 5 turns | 3 /turn | Master Philosopher | +20% | Habitable Land | Urban tile only Max 1/City |
| University Library | Scholarship | Legendary | 120 1 | 6 turns | 4 /turn | Elder Philosopher | +10% +30% | Habitable Land | Urban tile only Max 1/City |
 Cold Baths Baths |  Architecture | Developing | 40 1 | 4 turns | 2 /turn |  Apprentice Doctor | 2 | Habitable Land with access to Fresh Water | Urban tile only Max 1/City |
 Warm Baths Baths | Architecture | Strong | 60 1 | 5 turns | 3 /turn | Master Doctor | 3 | Habitable Land with access to Fresh Water | Urban tile only Max 1/City |
| Heated Baths Baths | Architecture | Legendary | 80 1 | 6 turns | 4 /turn | Elder Doctor | 4 +10% | Habitable Land with access to Fresh Water | Urban tile only Max 1/City |