Slitherine

I have noticed that in most of my cities the option for building peasants is greyed out. Why is it I can build peasants in some cities but not others? I have plenty of food in reserve. I have looked through the cities and can't seem to find a common factor, some that can build peasants are both higher and lower than others that can't in happiness, population, food resource value and bumber of buildings. Does anyone know what causes this? Is it just a glitch in the game or is there an undocumented requirement that I haven't figured out yet?

You must have unlocated population in your city...if people are busy, they can't enter an army

You need to free up a population unit first. If they are all employed, they are not available to recruit.

Aha ! I knew I was missing something. Thanks, guys.