How large should a 3rd/4th gen settlement be?

[Rift_Wolf]

I'm figuring out a fairly realistic world, and am stuck as to where to find relevant info to answer the above question. I don't want to just pluck numbers out of thin air; if I can say 'looking at X, the population would be similar', I'd prefer to do that.
Info;
Low/zero magic, early iron age; this would be the first settlement of this world, so no grand buildings yet.
Settlement is about 100 years old; the founding family is on its 4th generation, and the settlement would've grown from that first band of warriors into a peaceful settlement.
Humans only.

Would it be a small village by dnd standards? My gut says it'd be a settlement of hundreds, not thousands, but my gut isn't known for its accuracy.

[Mith]

What was the initial numbers for settling the area?

Off the top of my head (so this is likely unrealistic in the extreme), assuming that enough resources could be brought in to support the growth (agriculture and the like), the population could gain 30% each generation. The reasoning is that not everyone will make it to adulthood, and the adults may die as well, so the number of children being born and increasing the population will be balanced out by the deaths.

How I did the math (which is likely wrong) is as followed:

Assumption: Population is roughly split 50/50 by gender lines. Therefore, everyone has a spouse to have children with.

So if the average number of children produced by each family is 7 kids for every three families (as infant mortality is high, so not all kids make it to adulthood). Then the children's generation will be 33% larger then the parent generation ( (7 kids/3 families)-(6 parents/3 families) = 1 extra kid/ 3 families).

Now since my assumption of a 50/50 gender split is likely to be a bit off, and resources may be pretty scarce, I rounded the 33% increase to 30%.

This will only hold true to a point where the population is sustained at a single number. For the iron age, I would say 300 people for a small settlement, depending on how advanced they are in terms of hygiene and such for keeping disease down.

My numbers may be completely wrong, but I think the thought process behind generating rough numbers is at least somewhat sound.

[Solaris]

We definitely need to know how many we started with before we can tell you how many you have. If you started with less than a few hundred to a couple thousand, though, the answer is probably going to be "None". Pioneering is not the sort of work that has a good survival rate, especially at Iron Age tech levels.

You'd want an uneven gender split, with more men than women. Males tend to die off at higher rates during colonization.

[Rift_Wolf]

Okay done some number crunching and here's what I got. Feel free to shoot me down if the numbers look wrong.
Let's say the kingdom is the size of Lincolnshire, UK. Lincolnshire has an area of 6959sqkm, and 1/10th of the population lives in the central city of Lincoln. So for our Kingdom, we can say 1/10th of the population lives in the capital.
Now, iron age population density isn't particularly well known; I'm going out on a limb by looking at current population densities, as their numbers are more solid. Mongolia has one of the lowest population densities of modern times at 1.92 people per sqkm. I've read through 'guns, Germs and steel' which says 1 person per sqkm in iron ages would've been pretty sparse, so we'll keep 1.92 as our basis.
So a Kingdom the size of Lincolnshire with a population density of Mongolia (stay with me) would have 13661 inhabitants. A tenth of them live in the capital, so our founding tribe would be 1-1.5k strong. That's including women, children and non combatants as well as the band of warriors the King leads.
Now, Mongolias annual population growth rate is 1.37%. Going by 'guns, Germs and steel' again, the author claims an iron age growth rate of 1% would be 'trivial', so keeping 1.37% is probably on the low end of the growth spectrum. So after 100 years of growth, the kingdom has a population of 52093 (using a cumulative interest calculator). Rounding it down to 50,000 would make our capital city 5000 people strong.

Does this look about right?

[Rift_Wolf]

Sorry if I'm not being very clear; the idea behind this example Kingdom was that the first king has been the first person to rally enough people behind him to hold any appreciable territory. His settlement is the first one beyond tents or huts; there's still other small villages, nomads, etc that made up the pre-kingdom population. I was trying to figure out by how much a founding city would grow in a hundred years, and I think looking at population growth rates has given me an idea. But I was also trying to figure out the number of people who'd follow the King, and would make up the population of his first town/city. 1-1.5k seemed like a lot when I first started thinking about it, but crunching for a bit makes it look reasonable.

[jqavins]

There's a factor that has not been considered that 1) I'm pretty sure is of very great importance, and 2) I don't know how to incorporate. In other words, I don't know what to do with it, but I think you'd better do something.

The factor is: Why was this settlement founded in this place? Is/was it an agricultural village, housing farm families who work fields outside a wall? Is it a mining town? Is it a commercial center, where farmers (who live out on their fields) and miners and hunters/furriers, and so on all meet to do business? Are there few farms around and food imported or is the town in a fertile area? Etc. The lifestyle affects the population growth, undoubtedly, but I can't say just how. Just one example, farmers tended to have really big families, merchants not so much.

[sktarq]

Well there are other factors here too. With nomads etc in the region the growth rate must factor in immigrants and emigrants. Depending on culture some may switch due to marriage or a bad harvest or three could drive some homesteaders to leave.

Also the 2% growth rate would be low in an area well below carrying capacity assuming these people are producing a strong food surplus by agriculture.

As for diseases if this is your world's first town then there won't be many. Not in the human to human plague kind anyway. Unless the nomad population is both dense and highly interactive the pool of people able to host a disease would be pretty small and not large enough to gain new unexposed members before the remainder has either died or become resistant.

[Solaris]

As for diseases if this is your world's first town then there won't be many. Not in the human to human plague kind anyway. Unless the nomad population is both dense and highly interactive the pool of people able to host a disease would be pretty small and not large enough to gain new unexposed members before the remainder has either died or become resistant.

A lot of the really fun diseases are zoonotic. About two-thirds of all diseases came from animals.
Thus, new diseases for which the population has no protection is very much a genuine and valid concern. Bubonic plague, for example. Being nomadic is the exact opposite of a protection against it, as nomads tend to live close to their animals.

[sktarq]

Historical Zoonotic plagues are the norm but actually very rare and most that do cross over need extended time and contact to do so. So when an outbreak does occur it would be a short intense one and then the disease would disappear again. And with little population to carry human to human diseases this would really be the only significant source of plagues at all-thus my statement that they would much more rare than our own historical iron age.

A few plagues have animal reservoirs that can regularly infect human but those exceptions-most need to mutate to make human to human transitions.

Also most plagues have come from living for centuries of close contact with various animals and their parasites/dung

[Solaris]

You're thinking in too macro of a scale. That short but intense plague burns out because it runs out of victims. The next village over is fine, but the colony is gone. The plague isn't really less likely to happen, it's just less likely to spread across a continent.

Well, considering by the time our Iron Age started we had already long ago domesticated the dog, donkey, horse, sheep, pig, and cattle, the colonists have already spent centuries living near their animals unless the timeline is dramatically different.

[jqavins]

Historical Zoonotic plagues are the norm but actually very rare...

I'm sorry, but what does "It's the norm but it's very rare" mean?

[Rift_Wolf]

Several points to address but can't figure out how to do multiple quotes on phone, so here goes;

Type of settlement; I see it as a hunter-gatherer settlement that converted to farming following animal domestication (most importantly, horses). To use a terrible anachronism, the first king was meant to be leader of a band of horsemen, similar to the Mardu from Khan's of Tarkir or the Rohirrim. At the start of the kingdom, it'd still be basic stuff; it'd be a few years before permanent buildings were set up, and the King still has to quell any rivals to his claim. The tribe might have herdsmen who settle into sedentary farming. After a few generations, though, the population would be more likely to be farmers than hunters. With the kingdoms army protecting the land, small villages would pop up in fertile regions. The Kings settlement becomes the centre of his Kingdom.
TL ;DR farming community

Disease; I was under the impression close proximity to animals is what builds immunity to zoonotic diseases, and that's why Europeans had some immunity to smallpox (among others) when New World natives didn't. Yes for individuals the chance for cross infection rises, but survivors of cross infection pass on the immunity to their children (in a simplified, lets-not-get-into-disease-mutation-arguments world). And while yes, a lot of iron age settlements ended up dying out, some didn't. Some went on to become towns or cities. I'd like to write about those ones.

Emigration: as far as I'm aware, emigration is part of population growth rates. Spread out over 100 years, the growth rate would take into account statistic glitches (immigration swells, plagues, Bad crops) that could knock the number up or down.

Thanks for all the input, btw. It's given me a lot to think about for my story :)

[Solaris]

Disease; I was under the impression close proximity to animals is what builds immunity to zoonotic diseases, and that's why Europeans had some immunity to smallpox (among others) when New World natives didn't. Yes for individuals the chance for cross infection rises, but survivors of cross infection pass on the immunity to their children (in a simplified, lets-not-get-into-disease-mutation-arguments world). And while yes, a lot of iron age settlements ended up dying out, some didn't. Some went on to become towns or cities. I'd like to write about those ones.

It does this by process of natural selection; the survivors of zoonotic diseases tend to be more resistant on the average than the pre-infection population because only those whose primary immune responses could tool up sufficient reaction in time to stop the disease survived it and thus those whose antigen receptor genes lacked the ability to bind to antigens on the disease died. The reason Europeans had resistance to smallpox is because they had already experienced the nigh-apocalyptic effects of smallpox infection in the early ADs or so when it first arrived. I don't say 'immunity', because smallpox still took out about half a million Euros each year about the same time it was helping to do in the New World's population... and because the adaptive immune system doesn't work on Lamarckian principles.

[Rift_Wolf]

It does this by process of natural selection; the survivors of zoonotic diseases tend to be more resistant on the average than the pre-infection population because only those whose primary immune responses could tool up sufficient reaction in time to stop the disease survived it and thus those whose antigen receptor genes lacked the ability to bind to antigens on the disease died. The reason Europeans had resistance to smallpox is because they had already experienced the nigh-apocalyptic effects of smallpox infection in the early ADs or so when it first arrived. I don't say 'immunity', because smallpox still took out about half a million Euros each year about the same time it was helping to do in the New World's population... and because the adaptive immune system doesn't work on Lamarckian principles.

I didn't want to get into a debate over this as you clearly know your stuff while I'm going by what I've read in pop-science books. My understanding of disease resistance (rather than immunity, I misused the term) was that by domesticating large animals earlier in their history, Europeans were cross infected earlier in their history and suffered population bottlenecks which led to increased resistance through natural selection. Without domestication, those bottlenecks wouldn't have happened theoretically, and cross infection would've been more devastating when it occurred, such as in the new world.
However, like I said, writing about a developing settlement that gets wiped out by a plague is a fairly short and gruesome story. When I get round to writing significant events, perhaps the population does suffer a bottleneck after a plague. But at the moment I'm still figuring out basics.

In one of your first posts you said the starting population would have to be a few thousand or it'd be wiped out. After the number crunching I got somewhere between 1-1.5k. Is this number still too small?

[Solaris]

I didn't want to get into a debate over this as you clearly know your stuff while I'm going by what I've read in pop-science books. My understanding of disease resistance (rather than immunity, I misused the term) was that by domesticating large animals earlier in their history, Europeans were cross infected earlier in their history and suffered population bottlenecks which led to increased resistance through natural selection. Without domestication, those bottlenecks wouldn't have happened theoretically, and cross infection would've been more devastating when it occurred, such as in the new world.

Your understanding is correct, at least so far as I understand the subject; the simplified version you'd posted earlier read as... well, I've encountered enough people who have no idea how disease and genetics work to want to make sure you weren't operating under a mistaken assumption.

However, like I said, writing about a developing settlement that gets wiped out by a plague is a fairly short and gruesome story. When I get round to writing significant events, perhaps the population does suffer a bottleneck after a plague. But at the moment I'm still figuring out basics.

Oh yeah, you're not going to be wanting to write about one of the villages that gets wiped out - I'm only mentioning this because it's an element you'll want to keep in mind with the world-building, as this is the point in history where diseases really begin to start taking off.

In one of your first posts you said the starting population would have to be a few thousand or it'd be wiped out. After the number crunching I got somewhere between 1-1.5k. Is this number still too small?

It depends on how similar the colony is to the homeland. If you look at the example of the English colonists in the New World, they suffered dramatically because New England is similar to England in name only; it's colder, harsher, and far less forgiving of errors. If, however, the locale is fairly similar in its climate, flora, and fauna, then that number is, by my napkin math, solid enough to establish a sustainable population.

[sktarq]

I'm not thinking on a too macro scale. Because while most diseases come from a hop of animal to human the chance that will happen in any one village is tiny. Most plague don't start in your home village, as this is the only village patient zero has to be within the tiny population of the community.

Basically I'm saying that since the mutation that allows a microbe to handle human-to-human transfer is so rare and the basket of people so small the chances of developing significant amount of disease in this model is much lower than in the actual historical record.

Norm but rare explanation: most diseases came from an animal-to-human hop but any given exposure has a negligible chance of producing that hop. Thus a large population of people is needed to drive a massive number of human/animal exposures.

And nomads who have animals generally have less contact with thier ill animals than farmers due to co-habitation issues found in sedentary agriculture and that herds tend to me more tightly packed and prone to give the disease to all the other herd/flock/sounder members. And that is assuming the nomads are pastorealists and not hunter-gatherers.