Ancestral enemies?

[East Street Trader]

From time to time I have noticed happiness drop when I conclude a peace, or rise when I declare war.

Last night I had a particularly striking illustration of this. Playing the Zulus I attacked the Aztecs late on under democracy, having had little or nothing to do with them earlier. As soon as I did so about two thirds of my numerous cities immediately began to celebrate!

Does anyone know the mechanisms for this? Will war with anyone at all please some of the people (while eventually also causing war weariness when apropriate)? Or are there, as I rather suspect, some ancestral enemies which it pleases the populous to fight with?

[vmxa1]

It is the phenomenom that people will tend to rally around the flag, for awhile.

So you see when a civ declares on you some cities go into WLTKD.

[Dr. A. Cula]

Yes, and the WLTKD will last longer if your enemy declared war. However, you should sustain that with a quick victory.
There is also the opposite: if you lose a few cities in the beginning, war weariness gets higher almost instantly and will not decrease even if you eventually take back those cities and push further into the enemy's territory.