Low-Tech Kingdom Population Density?

[Sunrunners_Fire]

I have a low-tech fantasy kingdom, isolated from the rest of the world due to accidents of geography, history and magic. It is intended to be self-sufficient at TL 4~ and so can thereby be assumed to have a minimum population of 700,000 using the numbers on (GURPS Space, pg 91) as a guideline. The available geography for said kingdom is 3,472 square miles of arable land. With a minimum population of 700,000, this gives a minimum population density of 202~.

I'm not sure that is a reasonable number. If it is reasonable, how high can I take it before it becomes unreasonable? If it isn't reasonable, how low should I reduce it to? Sources so I can figure this out for myself are welcome!

(At 700,000~ population, it has a per-capita income of G$12,480, Average Wealth and an economic volume of G$8,736,000,000. It doesn't have a trade volume as it has no trade with outside kingdoms. Average Wealth's monthly income is G$800, a CR of 3, a MBF of 2% and so it has a G$11,200,000 monthly budget for the kingdom's military and police forces.)

[Peter Knutsen]

Do a google for: medieval demographics easy ross

[Dammann]

That kind of population density might work if 100% of the land was arable. Otherwise, I just don't see it. I think with S.J. Ross's Medieval Demographics, you could get an area that was 66% arable and population densities of 120~.

Edit: here is an automated version of the Ross thingie

[Peter Knutsen]

Originally Posted by Peter Knutsen

Do a google for: medieval demographics easy ross

And here is the proper link. I didn't have time to find and post it earlier.

[Polydamas]

Originally Posted by Sunrunners_Fire

I have a low-tech fantasy kingdom, isolated from the rest of the world due to accidents of geography, history and magic. It is intended to be self-sufficient at TL 4~ and so can thereby be assumed to have a minimum population of 700,000 using the numbers on (GURPS Space, pg 91) as a guideline. The available geography for said kingdom is 3,472 square miles of arable land. With a minimum population of 700,000, this gives a minimum population density of 202~.

I personally suspect that the population required to maintain TL 4 in isolation is in the tens of millions (see: Hellenistic/Roman Mediterranean, Tokugawa Japan). You can have towns and muskets with a much smaller population, but not amazing art and huge libraries and cities with hundreds of thousands of people and pocket multitools and large amounts of good steel armour and all kinds of specialists and ships of a thousand tuns burden. So you will need much more land, or a lower TL.

To give an idea, 700,000 people is one large TL 4 city like Ptolemaic Alexandria, imperial Rome, Queen Anne's London, Tokugawa Tokyo, or any of several Chinese capitals.

[Dammann]

Yes, but Magic.

[Sunrunners_Fire]

Originally Posted by Dammann

Edit: here is an automated version of the Ross thingie

Originally Posted by Peter Knutsen

And here is the proper link. I didn't have time to find and post it earlier.

Thanks, both of you.

Originally Posted by Dammann

Yes, but Magic.

I was attempting to determine if it was reasonable prior to factoring in their magics. Looks like it isn't. Too high of a population density for their arable land at that level of technology, too low of a population to maintain said technologies. I can adjust the population values up and down, but the arable land available is a fixed value.

Ah well.

[Sunrunners_Fire]

Originally Posted by Polydamas

I personally suspect that the population required to maintain TL 4 in isolation is in the tens of millions (see: Hellenistic/Roman Mediterranean, Tokugawa Japan). You can have towns and muskets with a much smaller population, but not amazing art and huge libraries and cities with hundreds of thousands of people and pocket multitools and large amounts of good steel armour and all kinds of specialists and ships of a thousand tuns burden. So you will need much more land, or a lower TL.

What then do you consider the minimum population to maintain TL 4~?

Not develop it (as they didn't develop it themselves in the first place), but maintain an existing body of knowledge and the infrastructure necessary to make use of it?

[Turhan's Bey Company]

I'm late to the population density party, but there's an article in Pyramid #52 which covers land use and support of urban centers. You can use that to figure out population densities in a GURPS-friendly way.

I suspect you'd need a population of several millions, if not tens of millions, to do TL4. In addition to encompassing a great many craft industries, those industries imply a lot of specialized extraction and processing industries, which in turn imply the need to cover a lot of space and to be supported by a vastly larger population. Moreover, without a large and well-populated setting, some of the hallmarks of TL4 civilizations (elaborate architecture, various navigational developments) won't be practice, and since these are things which are generally transmitted by what amounts to oral tradition rather than by reference books, they'll vanish if they don't get used.

[Sunrunners_Fire]

Originally Posted by Turhan's Bey Company

I'm late to the population density party, but there's an article in Pyramid #52 which covers land use and support of urban centers. You can use that to figure out population densities in a GURPS-friendly way.

Ah. Thanks for the reference, I'll poke at it when I'm next able to grab something from the store.

Originally Posted by Turhan's Bey Company

I suspect you'd need a population of several millions, if not tens of millions, to do TL4. In addition to encompassing a great many craft industries, those industries imply a lot of specialized extraction and processing industries, which in turn imply the need to cover a lot of space and to be supported by a vastly larger population. Moreover, without a large and well-populated setting, some of the hallmarks of TL4 civilizations (elaborate architecture, various navigational developments) won't be practice, and since these are things which are generally transmitted by what amounts to oral tradition rather than by reference books, they'll vanish if they don't get used.

TL 4 is noted as starting in the 1450s. Europe had around 50 million people at that point in time and the British Isles around 3 million people. If we cut the British Isles of the 1450s off from the rest of the world, you are saying that the Isles wouldn't be able to maintain their technology base but would instead revert down to ... TL 2 or so?