Note: This article explores the population limits of fantasy worlds.
While it is part of my World of Glain, much of what appears here
should apply to any fantasy role-playing campaign.
In the real world, in early to middle medieval times, a farm family
required about 35 to 40 acres for subsistence-level farming. In most
regions of Europe, a village of farmers would be arranged around a
central green where what little livestock they could afford was
allowed to graze. Around the outside of the village were arrayed the
fields. This was called an "open field" system, where no walls or
fences separated the fields, and the villagers worked the fields in a
Due to the lack of herbicides, pesticides, and fertilizer, farming was
much less productive than it is today (or even a hundred years ago).
A minimum of ten farm families would be required to support one urban
family; this was the primary limiting factor to the size of towns.
However, this is a fantasy world we are dealing with here. In the
real world, most villages would have had a small church consuming
part of the villager's grain as tithes. In a fantasy world, the local
church or temple will still expect tithes, but in return the local
cleric (assuming he or she is at least third level) will provide such
services as healing the injured (including the valuable livestock),
using Augury to determine whether or not certain activities are
advisable, etc., increasing the productivity of the local farmers
dramatically. Higher level clerics will be able to provide even
Technology was also a problem for the medieval farmer; their plows
were inefficient, requiring double plowing (criss-cross), and were
drawn by strong but slow oxen. Not until the late Middle Ages did
farmers gain access to horse-drawn metal plows with moulding boards
(to turn over the soil). This, coupled with the addition of legumes
(which nitrogenate the soil) as a crop, increased the yield of the
medieval farmer dramatically.
This level of technology is readily available in Glain. As a result,
each square mile of average quality farmland will have about eight
farm families, each with about 80 acres of land to work. Even in
nations where land may not be owned by commoners, each farm family
will have land allocated for their use specifically. Each square mile
of land can support two urban families (a 4 to 1 ratio, much better
than the old 10 to 1 ratio). Naturally, land quality can cause this
figure to vary, possibly greatly.
So the formula is simple: For each urban family (assume about four
persons per family), one-half square mile of territory and four farm
families are required for their support. This also means that, for
each square mile of territory around a city, there will be about ten
families total (eight families of farmers and two of city dwellers),
and at the average of four per family this results in 40 people
supported per square mile.
Looked at in reverse, given a population of 1,000 city dwellers, how
much land is required to be cleared around the city? Those 1,000 city
dwellers work out to about 250 families, and they must be supported by
four times as many farm families (1,000 such families to be precise).
Those 1,000 farm families each need 1/8th of a square mile, so 125
square miles of cleared land are needed.
In other words, the calculation of required farmland around a city is
simply the population divided by eight in square miles. Were this
land arranged in a circle around the city, the radius of the circle
would be equal to the square root of the (area / pi), which in this
case is about 6.3 miles. Naturally such an arrangement is unlikely,
but might be useful as a rule of thumb. Below is a table of common
city sizes and the required farmland. I have rounded fractions up for
||Square Miles of Farmland Required
||Radius of Circle
The maximum size of a city is bounded also by the distance to the
farthest outlying farms, or more exactly to the time it takes to bring
crops and livestock to market in the city. Travelling with cattle,
pigs, etc. is done at half the usual rate of travel afoot, so a human
farmer moving livestock to market can travel twelve miles on trails in
flat land, or about six miles in rolling terrain. Roads improve the
movement rate in hills to twelve miles per day. Travel rates for
carts loaded with harvested crops will be similar.
If the transport of goods to market takes more than one day (one way),
spoilage or other loss becomes an issue. Most farmers won't risk a
longer trip; if a farmer can't deliver his goods and be home the next
day he most likely won't make the trip. This makes the usual maximum
radius about twelve miles, or between 2000 and 5000 population for the
city. Given that arriving earlier in the day is the farmer's best bet
for making a profit, farmers in outlying areas would likely leave home at
dawn. Those within six miles or less will arrive at or before noon,
and get the best prices for their goods. Thus, cities of 1000-2000
population will be much more common than those larger cities.
In very civilized regions there may be merchants who specialize in
buying goods from farmers and transporting them to the city for a
profit. This is only likely to be the case near the larger cities
given above. Such merchants will have better equipment (carts, etc.)
for transporting such goods than the average farmer, and may employ
armed guards in more dangerous territories.