Roman Legions

[Rome:Total Slayer]

OOOOOOOOOHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!1

[PseRamesses]

Another way to manage population in large chunks is to give one of your large cities, that is growing too fast for your building browser to keep up, to a faction that you´re at war with and simply retake it in the same turn. Now you can either enslave or exterminate its population.
And you probably already know this one; before assaulting a city, and want to enslave its population, remove all govenors in cities that you don´t want to grow. Now all slaves are directed to only the cities that you still have a govenor in. Good luck!