Culture Flipping?

[mrmitchell]

Through a set of discoveries I found a brand new peninsula to colonize in early Midieval. (I only have a sea route to it, if that helps.) However, the Aztecs found out too, and were set to colonize it. I plant four cities down and so do the Aztec. I start building temples everywhere, and then New Oceaopolis' temple is complete so I set it to Colosseum.

Lo and behold, the military advisor pops up and says New Oceaopolis has flipped to the Aztecs because of Atzacapawhatever.

I investigate Atz, and it doesn't even have a Temple!

However, there are two more cities close to New Oceaopolis and I didn't have the cash to investigate them.

So, I guess my basic question is: what's the formula for culture flipping? Can other cities actually do the culture-flipping and the advisor just says the name of the closest rival city to flip to, regardless of its own culture?

[zeh]

Maybe I'm wrong, but I never saw the name of a city when the Military advisor tell about a cultural flip, they only say my city gone because it's an admire of some civ culture. So one of the reasons is the total culture, not only one city.
Of course there's a lot of factors, try search for something "flip formula".
BTW, I think you can almost always prevent a cultural flip by fortifing sufficient military units in border cities.