Medieval Demographics

For a fully developed medieval country, the population density will range from 12 people per square kilometers, if the region is at constant war, has gloomy weather or inhospitable terrain, to 48 per square kilometers, for region with rich soil, favorable seasons, etc.

¹For some context, in the XIV century, in Germany, the density was about 24 people per sqkm, in the same period, Sicily had the lowest population density of the southern Italy, with 19,4 people per sqkm. Tuscany, on the other hand, had at least three times as such, if not four times the population density of Sicily, between 60 and 80 people per sqkm.
French in the XIV century had a density just upwards of 38 people per sqkm, the British Isles, had a population density of 15 people per sqkm, mostly squashed in the souther parts of the archipelago.

Randomly generating population densities

To roll randomly population density, something like this might work:
Roll $4d4\times 5$, the multiplier $5$ can be reduced down to $1$ to represent a gradient of going from high developed areas, to wilder, less-developed lands, or to represent countries depopulated by invasion, plague, or other calamities.
If you want to generate randomly varied regions, you can replace the multiplier with a roll of a $d6$.

Town and Cities

• Villages (Villaggi): from 20 to 1000 people, typically around 50-300 people. Most kingdoms will have thousands of them. These are agrarian communities, within the safe areas of civilization, providing food and land-stability to the realms.
• Towns (Cittadine): from 1000 to 8000 people, typically around 2500 people. These tends to have walls only if they’re politically important and/or frequently threatened.
• Cities (Città): from 8000 to 12000 people. Large kingdoms usually have only a few cities with a population this large. Centers of scholarly pursuits (Universities) tend to be in cities of this size.
• Big Cities (Grandi città e/o Capitali): from 12000 to 100000+ people. Some historical examples are London, Paris, Genoa, Venice and Moscow.

Large population centers are usually the result of traffic: coastlines, navigable rivers, and overland trade-routes form a criss-crossing patterns of arteries and towns and cities grow along these lines. The larger are these arteries, the larger the cities are going to be. Villages are scattered densely trough the country between the larger settlements.

Population Spread

This is a simple algorithm for calculating the population spread for a kingdom.

• Determine the population of the largest city in the kingdom. This can be estimated by $P\times M$ where $P$ is $\sqrt{county\_population}$ and $M$ is a random roll of $2d4+10$ (average: 15).
• The second-ranking city will be from 20-80% of the size of the largest. You can roll this by rolling $2d4\times 10\%$ (average 50%).
• The remaining city will be from 10% to 40% smaller than the previous one ($2d4\times 5\%$, average 25%); continue listing cities for as long as the results maintain a city-scaled population (8000+).
• The number of towns can be estimated by $number\_of\_cities\times 2d8$ (average result is 9).

The remaining population live in villages, smaller settlements or isolated dwellings.

The ration of towns to cities given above presumes the existence of a thriving mercantile community. You can adjust the number of towns upward by 50% or more for a world on the verge of Renaissance, or adjust it sharply downward for a pre-Crusades type of world.
Historically, the number of town charters in many European countries multiplied nearly by 10 from the XI-XIII centuries as economic shifts reshaped the agrariann scheme into something more robustly mercantile.

Agriculture

A square kilometer of cultivated land, will support around 70 people, taking into account blights, rats, droughts, and theft. If aided by magic, this number could go up.

Other useful metrics

1 squared kilometers equals to 100 hectares.
1 hectares of cultivated lands supports 0.7 people.
1 person needs 1.4 hectares of cultivated land to survive.

However, for some region like medieval Italy, 70 people per square kilometers is really achievable only in very fertile region and in prosperous periods. A more sound number could be around 35-50 people per square kilometer, in normal conditions.

An average family need around:

Parameter	Estimated values
Family Composition	~5 people (2 adults, 3 children)
Cereal need of the family	≈ 5 kg a day = ~18 quintals per year
Necessary land	≈ 14 hectares per family
Actually possessed and cultivated land	< 10 hectares in average (≈50% of what they needed)

Long version of Medieval Italy research for more robust estimates

Population Density:

• Around 1300, Italy was among the most densely populated regions in Europe, with an average territorial density of 40–50 people per km² — much higher in fertile plains like Tuscany or the Po Valley.
• However, this figure includes mountains and forests. For cultivated farmland, local densities could reach 70–80 people per km² in rich areas near cities.

Agricultural Productivity:

• Medieval farming used primitive techniques: two- or three-field rotation, low-yield seeds, heavy reliance on fallow land, and limited fertilization.
• Typical grain yields were about 0.5–1 ton per hectare per year, far below modern levels (4–6 tons/ha).
• Part of the harvest (about 25–30%) was reserved as seed for the next year.

Food Needs vs. Land:

• A physically active medieval adult needed ~2,500–3,000 kcal/day.
• This required about 200–300 kg of cereals per person per year.
• Considering low yields, taxes, and fallow, each person needed on average 2–3 hectares of farmland for stable self-sufficiency.

Crises & Sustainability:

• High local densities (~70 people per km² of farmland) were reached but were barely sustainable, leading to constant risk of famine, reliance on food imports, and vulnerability to bad harvests, war, or plague.
• After the Black Death (1348), population fell sharply (losses up to 50% in some areas), and many marginal lands were abandoned, lowering effective rural densities to 40–50 people per km² or less.

Bottom Line:

• 70 people per km² of cultivated land was realistic only in the most fertile, intensively farmed areas at peak population, but it was not sustainable long-term with medieval technology.
• On average, a more stable figure for the late medieval Italian countryside was 30–50 people per km² of farmland — implying ~2–3 hectares per person.

Bibliography:

• Carlo M. Cipolla – Before the Industrial Revolution: European Society and Economy 1000–1700
  • Covers population density, agricultural productivity, and grain yields in medieval Europe, with examples from Italy.
  • Backs up the ~0.5–1 ton/ha yields and the link between land use and subsistence.
• Massimo Montanari – La fame e l’abbondanza: Storia dell’alimentazione in Europa
  • Discusses food production, diet, and the caloric needs of medieval peasants.
  • Confirms the 200–300 kg/year/person grain estimate and general nutritional needs.
• Giovanni Federico – An Economic History of the Silk Industry, 1830–1930 (esp. intro chapters on pre-industrial agriculture)
  • Useful for understanding long-term agricultural constraints and productivity before modernization.
• Paolo Malanima – Pre-modern European Economy: One Thousand Years (10th–19th Centuries)
  • A quantitative and regional analysis of European economic development, including land use and population.
  • Provides data on Italy’s population density (~40–50/km²) and the shift after the Black Death.
• Luca Mocarelli – The Rural World and the City in Late Medieval Italy (in various edited volumes)
  • Explores the pressures of urbanization on rural land, the contado system, and food imports to cities.

Castles

While this is very world-oriented, you can safely take that there is a functioning castle for every 50,000 people. 75% of these castles will be near civilized areas of the kingdom, the rest will be isolated or near borders.

Merchants and Services

Each type of business has a Support Value (SV), meaning the number of people it takes to support a single business of that sort. You can adjust the SV table by a percentage equal to $(4d4-10)\times 10$. Those with the lowest SVs represent professions which attract the most prized artisans and experts to the city.

Other things. There will be one noble household per 200 population or so, one place of worship every 400 if there’s a clear “dominant” faith, but will be much more common if there are dozens of faiths with none dominant.
A well kept medieval city will have 1 law officer for every 150 citizens.
There will be a university for every 25 million people.
Livestock population, whole, will be roughly 2.2 times the human population, where $\frac{2}{3}$
will be fowl (chickens, geese, ducks, etc.) the rest will be dairy cows, goats, and meat animals like pig.

Business	SV	Business	SV
Shoemakers	150	Butchers	1,200
Furriers	250	Fishmongers	1,200
Maidservants	250	Beer-Sellers	1,400
Tailors	250	Buckle Makers	1,400
Barbers	350	Plasterers	1,400
Jewelers	400	Spice Merchants	1,400
Taverns/Restaurants	400	Blacksmiths	1,500
Old-Clothes	400	Painters	1,500
Pastrycooks	500	Doctors*	1,700
Masons	500	Roofers	1,800
Carpenters	550	Locksmiths	1,900
Weavers	600	Bathers	1,900
Chandlers	700	Ropemakers	1,900
Mercers	700	Inns	2,000
Coopers	700	Tanners	2,000
Bakers	800	Copyists	2,000
Watercarriers	850	Sculptors	2,000
Scabbardmakers	850	Rugmakers	2,000
Wine-Sellers	900	Harness-Makers	2,000
Hatmakers	950	Bleachers	2,100
Saddlers	1,000	Hay Merchants	2,300
Chicken Butchers	1,000	Cutlers	2,300
Pursemakers	1,100	Glovemakers	2,400
Woodsellers	2,400	Woodcarvers	2,400
Magic-Shops	2,800	Booksellers	6,300
Bookbinders	3,000	Illuminators	3,900
*These are licensed doctors. Total doctor SV is 350.

Footnotes

1. Source: Reti Medievali - Università degli Studi di Napoli Federico II. ↩