Hey thanks Oaty... good stuff!

If I could put some pieces together - correct me if wrong -

If the total is 50%, the guv's house is 20%, and each building is 5%, this is kind of implying that one has to replace 6 additional buildings, for the Penalty to be totally gone (50%-20%=30%, at 5% each = 6 buildings). Putting in your experience with Cyrene, it sounds like there's a "building counter" that adds one for each building a culture makes (max 6). Does this sound logical?

I personally had a strange situation - Kydonia (an island) had 4k people but only a guv's house - not any other buildings at all. It was owned by rebels and had several different factions' armies standing around blocking each others' movement, including a big stack of rebels outside the town - perhaps they got locked in a negative cash flow somehow; couldn't get back in the town?

Anyway, I just spent a lot of time playing with Culture Penalty (CP) after taking Kydonia and found that:

1) CP is 50% when I take Kydonia, but if I make a Villa it goes to 0% just like that. So, for oddball situations like this (very few buildings), there's probably a rule that "if there are no more foreign buildings, CP becomes 0".

2) Otherwise, any building I made (of any type, including walls and barracks) caused a decrease of 0 to 10 CPs. Usually 5, but sometimes 10, and a very few times, 0. Shrines were no better or worse than other buildings. (Known exception: governor's building, which is 20.)

3) The very first thing I built always got a +10 CP reduction. So I was often at only 35 CP (10+5) or even 30 CP (10+10) after my first building, never less than 35.

The above holds true for seven reloads and building various things until Kydonia was to 0%.

4) In reviewing the rest of my cities though, I see that a few of them are at 45 CP. They are all massacred towns which have not had time to reach their next level, and all I've built (probably) was to replace their temple.

Putting all this together, I'm thinking that there is some randomness in how much each building will lower CP. Also notice that you didn't have to replace the Egyptian stable in Cyrene, specifically - a new wall fixed the problem. So it may not matter which building, it's just a building "count". Which may very well mean you don't have to scrap old buildings - if you can build new ones (not yet built before), that's probably just as good. Of course, any upgrades serve the same purpose.

Also, one of two things is true (or both):

Either the proportion of "other" buildings matters, thus Kydonia acculturated pretty "fast" because it had VERY few (and also, my first idea, about "does that mean we only need 6?", is wrong),

and/or

Various other cultures are treated differently and acculturate faster or slower. Like, Romans may be "close" to Greeks (and easier to "convert"; needing fewer buildings), but "far" from Egypt. This could extend to the initial reduction, too. So, Kydonia was a "close" culture to me, but some of the other ones are not. (I know this is not a distance thing per se, because a couple of the 45% CPs are pretty close to my capitol.)

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Okay, there are some more observations. Anybody else want to spend some time reloading a lot of games?