I'm around turn 90 in my Sassanid campaign. The Huns swung through eastern Anatolia and burned half the cities on my border with the ERE. I have settled five of those cities. I'm not sure if there is a faction difference, but as the Sassanids, when I mouse over a ruin, I get a sword icon. Right clicking the sword icon on the ruins allows me to colonize the ruin. It costs about 9k on average and half the troops in the army that "attacks" the ruins will become settlers. The building plots slowly regenerate over time as the population grows. On a side note, the ERE sent three legions after the Hun horde that had been destroying their cities. The Huns retreated into my territory and the ERE marched right in after them, having multiple battles with the Huns over several turns, before destroying them and leaving my territory. I'm not really sure how I feel about that.
I'm having a completely different experience with family members. You've only got a few which you need to protect. I have the opposite. My family is so large that I've got innumerable loyalty issues and have fought two civil wars already. Every end of turn is a constant spam of loyalty warnings and illegitimate child births. This brings up my only gripe with the family tree. there is no way to "maximize" it so that you can see everything on it at once. I have to click + drag the tree around the screen to view parts of it.
Bookmarks