I played a game on Emperor difficulty where I ended up with all city states as allies and kept them with basically no effort.
Here's how to do this:
- Play as Byzantium on a Pangaea map.
- Rush Stonehenge to start accumulating faith.
- Build the Hagia Sofia for the free great prophet.
- Pick Papal Primacy as founder belief for the diplomacy bonus towards city states.
- Pick Itinerant Preachers as extra belief for spreading your religion 30% further (in practice it means that most unconverted cities will be exposed to the pressure from 1-2 more cities than usual. Also, this is the reason why you should pick Byzantium as they can take Itinerant Preachers when founding a religion, everyone else must wait until they're enhancing their religion)
- After founding your religion, "seed" two suitable city states with a missionary. Location is important, it's better to seed towards the center of the continent and it's better to seed an area which contains many cities within 13 tiles of each other.
- Get a second great prophet as soon as possible and pick Religious Texts to make your religion even more pervasive. It will start spreading like a wildfire at this point and give other religions no chance to establish themselves.
- Offer protection to all city states. Always condemn other civs who bully city states to avoid losing reputation.
- Get Aesthetics from the Patronage social policies tab. You'll quickly become friendly with all city states that follow your religion and they'll start giving you bonuses.
Now here's the interesting part: with the culture from friendly cultural city states, I was suddenly able to complete every single "generate culture" quest given from city states, effectively gaining lots of reputation for free. Initially I had to work a bit towards getting more allies, but the more allies you have, the easier many city state quests become and it quickly escalated to the point where I gained allies without every doing anything for them. I had to use one spy to stabilize the last city state that an AI tried to control by constantly rigging elections.
Here's how to do this:
- Play as Byzantium on a Pangaea map.
- Rush Stonehenge to start accumulating faith.
- Build the Hagia Sofia for the free great prophet.
- Pick Papal Primacy as founder belief for the diplomacy bonus towards city states.
- Pick Itinerant Preachers as extra belief for spreading your religion 30% further (in practice it means that most unconverted cities will be exposed to the pressure from 1-2 more cities than usual. Also, this is the reason why you should pick Byzantium as they can take Itinerant Preachers when founding a religion, everyone else must wait until they're enhancing their religion)
- After founding your religion, "seed" two suitable city states with a missionary. Location is important, it's better to seed towards the center of the continent and it's better to seed an area which contains many cities within 13 tiles of each other.
- Get a second great prophet as soon as possible and pick Religious Texts to make your religion even more pervasive. It will start spreading like a wildfire at this point and give other religions no chance to establish themselves.
- Offer protection to all city states. Always condemn other civs who bully city states to avoid losing reputation.
- Get Aesthetics from the Patronage social policies tab. You'll quickly become friendly with all city states that follow your religion and they'll start giving you bonuses.
Now here's the interesting part: with the culture from friendly cultural city states, I was suddenly able to complete every single "generate culture" quest given from city states, effectively gaining lots of reputation for free. Initially I had to work a bit towards getting more allies, but the more allies you have, the easier many city state quests become and it quickly escalated to the point where I gained allies without every doing anything for them. I had to use one spy to stabilize the last city state that an AI tried to control by constantly rigging elections.