Has anyone recognized any patterns to help predict the creation of Barbarian city-states? I've seen some very limited circumstantial evidence (one revert to a saved turn) that indicates they might appear on top of unexplored goodie-huts which are guarded by barbarians. I certainly would like to find a means of "cultivating" barbarian cities, in order to grab them once they are well established. Since they are by default at war with the player, one can neither convert them with a missionary, nor gift exotic units to them (like missionaries) to see what happens. Has anyone discovered any funky way to exploit a Barbarian City or potential city before taking it over?