Quote Originally Posted by Seasoned Alcoholic

You guys probably already know this, but I'd thought I'd include it in case any new modders browse through these posts looking for ideas. Have you double-checked each settlement core_building against level? I discovered this a while back, its easy to overlook as well. EG you have a govenors_house for a large_town etc.

For those of you who didn't know, the 5 levels are split amongst 6 core_building types, as listed below (off the top of my head ):

* Population: >=0 to <=999 --- village --- no core building
* Population: 1000 to <=1999 --- town --- govenors_house
* Population: 2000 to <=5999 --- large_town --- govenors_villa
* Population: 6000 to <=11999 --- city --- govenors_palace
* Population: 12000 to <=23999 --- large_city --- proconsuls palace
* Population: 24000+ --- huge_city --- imperial_palace

Of course, these are just guidelines, in the campaign you don't actually have to build a core_building type as soon as you hit a population level, as the excess will be carried over (and eventually countered by squalor).
Yes, I figured this out the hard way. Back in 1.2 I learned that you could lose the ability to upgrade the city level if you gave a population that exceeded the core building level.