I have the pagoda belief yet none of my cities let me purchase. All of them have my religion and I have plenty of faith but it won't even give me the option.
You can purchase a pagoda in a city if:
- The city's majority religion has the Pagodas follower belief- remember that the majority religion requires over half the population to follow it.
- The city doesn't already contain a Pagoda
- You have enough faith (though if you don't, the option will still appear greyed out).
- The city is not a puppet.
If all these are true, go to the buy menu in a city (you can't just build faith buildings) and the Pagoda will be there.