What exactly does this emergency mean?

[Zaimejs]

In the screenshot, you can see what I am asking. I am Saladin. I have converted the city to Taoism... now, apparently they are trying to stop me from converting the city for 16 turns.

Does this mean I have to convert the city and have it STAY my religion for all 16 turns? Or just manage to convert it by the end of those turns?

I was pretty sure I converted it, and I still lost, so I went back to the autosave to see what the emergency wanted me to do. It feels like I am missing something.

Thanks for help!

 

[679x]

Yea, the wording with this one is a little weird.
You need to keep the city mainly under your religion for as many turns as possible. The other civs are trying to remove your religion. IIRC the emergency lasts 30 turns total, so during those 30 turns, you need to keep your religion as the dominant religion in that city for at least 16 turns out of those 30 (doesn't need to be 16 consecutive turns).