Village population as a long term event

My group is currently in the fascinating process of designing a new covenant for Ars Magica 5th edition. The other day, one of my players asked how the population growth of a village could be simulated as a long-term event. For example, the covenant we are designing has a related mining village with 20 families of peasants. How will the population of this village evolve during time?

I have been searching in the rulebooks trying to find a way to do this but, so far, I have found nothing, so I was curious about how the rest of the Ars community is handling this during play. How do you do it in your sagas? (that is, if you consider this at all! :slight_smile:)

You could always simplify it by increasing by a factor of 10 every 20 years if you consider that most medieval families were large by necessity so average 10 children per family and deem half of them of marriage age already at the start of the saga. After first ten years all the second generation are married and each has 5 children, second ten years they have 5 more and then marry off half of third generation before the first 20 years and so on...

Might not be demographically sound process but its neat and easily calculated IMO.

Then again, you could always complicate it if you wish by factoring in a presumed percentage of infant deaths, deaths in childbirth, mine accidents that kill off some of the parents, etc, but thats' up to you.

course I'm no mathematician so feel free to shoot my idea down in flames :wink:

I would say that population growth is tied up in mundane politics.

Basically, those villagers are paying taxes to somebody, and therefore in the eyes of mundane lords they are a source of revenue. So either the local potentate is very happy (if the money goes to him) or not-so-happy (if it goes to the covenant).

As the village gets bigger, the degree of happiness or unhappiness will grow proportionally, IMO. That is to say, the village might not be important now, but if it grows over a period of decades, eventually it will become important.

As to the population growth rate -- that is an interesting topic and not too well understood/agreed upon by historians, but I would use a figure of around 5% per year.

As AG hints at, not everything can be predicted with a sheet of log paper and a straight edge.

Depending on the exact period, culture and legal system, peasants were not only seen as a resource, but as chattel. They were there to work, to serve, occasionally to war, and little regard was given to them "as people", or for their concerns as such. As well as, and perhaps more than politics, population growth in Medieval times was tied directly to agriculture, and at a subsistence level there was precious little spare food at that level to invite growth - if there was anything "to spare", it was taxed. Not very enlightened, if pragmatic in the short run.

My background in agricultural archeology is tentative, but iirc Europe was essentially NOT growing during this period, or not very quickly. Hand to mouth did not promote large families. (Do I remember that this was not changed until the invention of the steel plow? Some improvement centuries later in the horse harness? Something like that.) A village, and more importantly the fields that fed it, were often literally carved by hand from the dense forests of Europe. (You know, those dense forests!) Without growth, there was no real incentive to expand (not without a lords approval or encouragement!), and without expansion there was no growth.

At 5%/annum, that would be a doubling in perhaps 15(?) years - a bit over optimistic without organized infrastructure improvements. And given mundane methods, expanding an agricultural base is a very slow, laborious process, and one that Lords would be quite aware of, and probably question if they had not approved it.

However, with magic, many things do change radically. Lands could be cleared (not only of trees, but of stones, and generally leveled) far more quickly, and the arable land that exists can be made far more productive, providing the food to support a family size where the # of children surviving to adulthood is > than the parents, thus growth. Improvements can be hidden, and lords can be encouraged to be... amenable to those changes.

That said, such organic growth is slow, regardless. And given that slow process, there are a long hierarchy of "lords" would be quite aware of it - and that might not be desired, at one level any more than another.

"Where do Covenants get their food from?"

"Attracting Peasants"

Maybe some of those approaches would be more practical, all in all?

It highly depends you help them or not. If not, about 0,002% is the general growing process per year in average. If yes, it may rise even up to 0,0066%. Help means regular magical healing, say 2-4 hours per week and feeding them during famines.

But does this calculation have some sense? I have doubts.

Actually Cuchul, Europe at this time was exploding. with the advent of guilds and a merchant/craftsmen class, the feudal order was rapidly changing. People were gaining never before heard of wealth, cities were expanding, etc. It was in the context of this increasing popular sense of more widespread privilege that revolutionary subgroups like the cathars, Waldensians etc. were able to gain increasing numbers into their folds against previous traditional hegemony of the Vatican and the feudal order.

Of course there were backlashes in the vain attempt to reassert traditional hierarchical domination but 1220 is considered the High Middle Ages, your image is seemingly more that of the low Middle Ages.

Because of the changing order, the growing public wealth, the increase of craft industries, greater mobility etc, the population swelled over the next hundred years as never before. Apparently this significant population increase played an important part in the causation of the black plague a little more than a century later.



Eh, again, I'm no expert, and it's been a year or three (ahem) since I cracked a book on it, but "exploding" seems a bit over-enthusiastic a word. Or, perhaps, any growth compared to almost none is "exploding".

Okay, bring out the big guns...

[20 minutes of web research later]

Okay, the modern horse collar (which I was admittedly hazy on) showed up somewhere well before the millenium:
The Franks invented (or at least perfected) the horse collar, the wheeled moldboard plow, three-field crop rotation, the stirrup, and the water wheel.

(The Franks run was from about the 5th century to the 8th) So, it wasn't that - all that helped spark the so-called "growth" mentioned below...

(But I knew a plow was in there somewhere...)

Standardized Latin and Medieval Economic Growth

BLUM, Ulrich
DUDLEY, Leonard
University of Montreal ... er/360.pdf

[i]Between 1000 and the Black Death of the fourteenth century, an acceleration in economic growth permitted Western Europe to double its population. Traditional explanations attribute this upswing to favorable shocks -- an end to external invasions, an autonomous rise in trade or the establishment of feudal institutions. Implicitly, once the effects of these shocks had worn off, the region returned to its pre-industrial Malthusian equilibrium. However, Jones (1987) and Maddison (2001) have suggested that Western Europe’s per-capita income rose considerably between 1000 and 1500. To the extent that these estimates are accurate, one must look elsewhere for the sources of growth in the High Middle Ages.

Innis (1950) suggested that the key to understanding the medieval European economy was a new information technology (IT) ... More recently, Wright (1982, 1991) ... standardized forms of both written and spoken forms of a vehicular language -- medieval Latin -- that allowed people of different dialects to communicate with one another...

This paper presented an argument based on transaction costs that captures this IT hypothesis. The transactions-cost model predicts that by reducing the cost of contracting, a standardization of easily decoded information technology will lead first, to a collapse of hierarchical structures and second, to an increase in the marginal productivity of human capital. During the High Middle Ages, urban growth in Western Europe appears to have followed this pattern. Rapid economic growth was concentrated within a ring that stretched from the North Sea through northern and southeastern France into northern Italy. Cities outside the ring grew to the extent that they supplied the ring cities with human capital.[/i]
Meh, not the most on-point citation, but it seems to support my main point - that relatively nothing was "exploding" at this time (tho' perhaps was becoming poised for it). Now, I was wrong that it was "stagnant", which it had been pre 1000, but the blossom of the renaissance was centuries away.

So, the main growth seems to have been urban, and it took some 400 years for Europe to double. My calc isn't what it used to be, but that's somewhere below 5%/year - quite possibly below .5%.

Reading the paper fully also touches on the concept of innovation, or lack thereof. That, in the absence of impetus from a lord of some sort (be that noble or eclisiastic), a population base tended to keep doing exactly what it had been, and at the same scale.

So, I restate my assertion, that nothing was much growing at this time. Doubling in 400 years is not growth, except in comparison to the absolute stagnation of the first millenia. Even tho' compared to centuries of nothing, or worse in the case of some Roman territories, it was a friggin' explosion. :wink:

(Of course, if someone actually ~knows~ what they're talking about, please jump right in and slap some authority into this discussion, one way or another!) :laughing:

If you're looking for great details for your covenant, I assume you've already read the Covenants supplement. I'd also recommend picking up other books that deal with similar topics if you're interested.

A Magical Medieval Society: Western Europe is a book for D&D, but provides good details on the workings and economics of a manor, including explanations of the agricultural year's work, and a system to economically simulate the manor which I think does include growth. Some adaptation to ArM would be necessary, but the great detail would surely help you envision things at the very least. And it's available online (12$ here; you can check out the table of contents for free) as well as in print. (The book also includes details on cities and so on, but that's rather irrelevant to your issue, I guess.) This of course won't perfectly historically accurate, but would be close - the authors clearly invested some research and thought into this.

Well, no matter how fast the population grew exactly. The 12th and 13th century saw an expansion of agriculturally used land that had not been seen since the time of the Romans. Forests were cleared and civilisation pushed into lands never touched before.
This lead to the "Guardians of the Forest" ruling in the Rhine Tribunal and the splitting of House Bjonaer into harmonists and wilderists to meet the threat to magical resources.
So restricting the growth of your convent's village does have advantages:

  1. You keep a low profile
  2. Your magical resources are endangered less.
  3. You keep peace with some militant wilderist... Though this might evolve into an interesting story, Wizard's war and Tribunal charges included... :slight_smile:

Well, like any virus, if it grew 100% in 400 years, half of that wasn't in the first 200. :wink:

Yes, that's exactly I wrote earlier: 0,2% growth per year. (I calculated with 350 years.)
If we assume in the first half a lower and later a bigger growth you can calculate with 0,15 and 0,25% per year.

Famines, wars, plagues are all involved in this ratio of course.

Although, if you are actually in one of the cities or towns, this looks a lot bigger, because you are scavenging people from the countryside through urban drift. That is, the population concentrates somewhat in the period.

You also need to figure on emigration/imigration.

If conditions are really terrible, then people will flee. If it is a haven for refugees (like people who get in trouble with the lords), then a considerable growth will occur. (This is the primary reason for growth in the cities)

This growth/decline is not really dependant on the current population of the village, but rather on the surrounding area.

As for the organic growth, it should be considerably more than the .2% mentioned, I'd say closer to 10% per year.
But if you're drafting young people to serve as grogs, and lose them, then this will affect you population... And so on and so forth...

I'll second that opinion. That book is fantastic, and I actually stopped by Expeditious Retreat Press' booth at GenCon, they're working on a second edition. That's a great resource for looking at how magic could impact the medieval world-- say a village caught in a magic regio?


I should also add the Harn Manor has a detailed village creation system. It's a bit complex and Harn Pounds and Mythic Pounds don't quite match up (ars has 5-6 villages producing a surplus of 100 pounds, Harn has I believe one).


First of all, thank you to everyone for your useful answers. The doubt we had was more in line with what ulf commented.

We were curious about how many grogs, craftsmen, specialists ... will be available for recruiting at a given time and how this recruiting will affect the village. Also, since our saga will take place in the Iberian Peninsula around 1200 when there were a lot of battles and wars going on, I wondered whether there was a system to reflect the cost of war in population and available mundane resources for the covenant.

One thing I have noticed is that, in all cases, the figures provided were related to population increases. Don’t you think that population can also decrease, not only as a result of war and recruiting but due to bad living conditions created, for instance, by weather?

Or if you piss off the Storyguide, sure!

In the other hand, history bears out that once a person has "land", be it their own or just what they've been allotted, they tend not to want to give it up, especially in this period where the question "Where else would I go" cannot be answered by a glance at a Michelin Guide.

I refer again to the two links from other threads I posted, that talk more directly about this sort of thing.

But "mechanics" for this are almost useless. You're talking about making some very abstract, relatively complex decisions based on many factors - the only way to do that is become familiar with the material. Do some googling, do some reading.

Here's another, that everyone should have bookmarked:

While that doesn't address the question directly, it does give insight - if a burg doesn't have all that, it won't be "comfortable" to live there. And either that sort of person will gravitate there, or folk won't be excited about staying.

We can touch on surface topics, but they're just that. Go to the lib, get a good book on the topic, and read it, or the relevant chapter(s). Nothing like that for inspiration.

I'll second the Harn Manor suggestion, make sure you get the 2nd edition as I found the first edition produced too little surplus income. It has its own even event tables, and the detail allows for story ideas to crop up.

It would certainly be easy to abstract things by rolling for things like weather, pestilance, and crop production and then applying those to some arbitray average population increase factor.

I am more in the know on military things in the middle ages but everything I read on the economic situation was that it was doing fine up till the black plague hits. But "doing fine" is of course qualitative and not quantitative. A trip to your local collage or university library or just going to Amazon I am sure will yield a book with the accurate information.