Medieval Demographics Made Easy," written by one S. John Ross. In this article, Ross looks at real world examples of medieval demographics and then uses those examples to extrapolate what an pseudo-European fantasy setting might look like.
The articles examines several key factors for world-building:
- Population Density - in other words, how many people (on average) live within a square mile of the kingdom in question.
- Population of the Cities, Towns, and Villages - in other words, given that population density, how many cities, towns, and villages would be expected, and what would the population of those settlements be.
- Merchants and Services - in other words, given the population of a particular settlement, what kinds of goods and services would be available there. After some general guidelines, the article looks in more details about agriculture, castles, law enforcement, institutions of higher learning, and livestock.
So next time you've got some questions about what medieval demographics might look like, you've got an easy resource at your fingertips!