Now I have basic world generation for my fictional island realms. Like I pointed out in the last post, these realms are about 500 x 500 miles in size (which coincidentally is about the size of France). The perfect size for a number of kingdoms to fight over the resources the island has to offer. I like to think of this aspect of Fief as a very complex game of Catan.
Anyway, I now have kingdoms settling on the island and expanding. I don’t do any crazy history calculations or evolve it over time like Dwarf Fortress does. But I do retrograde things to account for the expansion of a kingdom. Things like vegetation, rainfall, and elevation determine how readily a civilization will expand, limited by a distance factor from their first settlement. This creates civilizations that very quickly expand if resources are readily available (such as a seaside, forest kingdom) or very slowly if resources are more limited (such as a dry steppe kingdom). I also do some vegetation degradation to account for a kingdom harvesting resources for a few centuries in the region it occupies. But keep in mind that things are set to be about 900 A.D. (in an equivalent Earth time period) as far as technology goes. So towns and cities are quite rare. Later when the technology and research arc is added in, perhaps you’ll be able to choose a later period and see more active cities.
Here’s an example of the standard map with civilizations displayed (by color), each dot is a fortress/town/city depending on the civilizations demographics. Each colored square is claimed territory for that kingdom and may contain an agricultural manor, a village, or just wild territory. In this map, the wet southern portion is dominated by larger kingdoms, while smaller kingdoms control the dry and rough territories to the north. This distribution is quite like the British Isles. Here you can see the settlements for each civilization (by color).
Here (with the settlements and domain territory removed) you can see the vegetation degradation caused by settlements.

Here you can see the vegetation degradation caused by the settlements.
And for the sake of completeness, here’s the elevation/rainfall map:

Combination elevation map (lighter is higher) and rainfall (redder is dry, bluer is wet).