Latifundia of the City State

Vladicu commented:
"Comment: Latifundia is an unexpected and excellent social label."

I think intensive commercial Roman-style slave farms work well with what we know of the City State - eg lots of urban nobility and a huge slave market. The Latifundia plantation system supports both of those.  I'm thinking a square mile of farmland in the exceptionally rich belt between the Mermist and Troll Fens takes around 50 healthy adult labour slaves to farm and produces crops for around five times that many, around 250/sq mile.  Actual population probably around 150/square mile, so an excess of food of 100 persons/sq mile.  With around 800 square miles of food-producing farmland that's food for 80,000, which is the population of the City State. Tweak as desired. 

Note that this system depends on constant import of fresh labour slaves - healthy male adult humans and similar, worked until they die.  If you start letting the slaves have families, wives & children, letting the old retire etc, then the excess population supported goes way down, with disastrous consequences for the City State.   

Latifundia-based farming:  150/square mile, excess 100/square mile supports 80,000.  Result:  Happiness (for the City State).

Feudal-based farming:  200/square mile, excess 50/square mile supports 40,000.  Result:  Misery (for the City State).