Blessed Cold: North America, Part 1

[Pedant]

To start with, a quick research question: does anyone know any good books about the various sects of Buddhism practiced by the Sōhei warrior-monks?

EDIT: this is a world where the Post-Roman Cold Period (400-900) and the Little Ice Age (1250-1850) swap intensities and duration. As a result of this, Britain became its own empire centuries early, North Africa is now Zoroastrian and Persian-speaking, Judaism has really branched out and incorporated various Arabian tribes into its fold, Mongolia successfully invaded Japan and were only kicked out recently, Vínland survived, the Americas had time to rebuild from smallpox annihilation before more Europeans came along, the Maya are the most powerful civilization in Central America, and (somehow) there are still giant moa and (more worryingly) giant eagles in New Zealand.
Current languages under construction: Alanic (Old and Modern), Common Brythonic (Welsh with a bit of Latinization), Vínlandic (think Greenlandic Norse but with more Mi'kmaq to it), Gothian (if French had been influenced by Visigothic instead of the Celtic languages and Frankish), Qhuric (the language of the surviving Ammonites, descended from the Ammonitic common at the time the Torah was being compiled), Common Arabic (with a dash of Himyaritic on account of the large influence of Yemen on the rest of the peninsula), Hunnic (a Finno-Ugric language with a large dollop of Turkic and Iranian vocabulary), and probably a great many others that I haven't gotten around to figuring out yet...

[mèþru]

Not about them, but they play significant rule in The Tale of the Heike

[Pedant]

Not about them, but they play significant rule in The Tale of the Heike

Ta!

[Pedant]

Also, as a quick side-shot, Blessed Cold's version of NORTH AMERICA (Part I):

Turtle Island (Mik'maq Migjigj Mnigu) is the third-largest continent in the world, coming behind Asia and Africa. It can be divided into three regions, moving from the Pacific to the Atlantic: the Cordillera, a Cretaceous-era complex of mountains and basins stretching from *Alaska to the *Yucatán; the Shield, comprising most of the northern half of the continent (including Greenland), which where it's not filled in with ice, marshes, or bogs is covered by immense boreal forests; the Interior Lowland, comprising the Great Plains and the Interior Plains; and the Eastern Region, bordering the Atlantic coastline, with the *Appalachian Mountains and the *Florida Peninsula forming adjoining subregions to the main. Humanity arrived on the continent some 19,000 years ago, across the *Bering Strait (at that time above sea level); there has been much intermingling, intermixing, and internecine conflict since that time.
In our own timeline, it has been reckoned that some 90% of the indigenous population was wiped out via diseases brought over from Europe, simply because there was not enough time to develop an immunity before more settlers came. In the timeline of the Blessed Cold, there was a similar extinction–but because initial European settlement took place in the year 1002, with the Norse colony of Vínland (originally Nyfundinnland, but apparently that was a bit too obvious a name), and it has been estimated to take about five generations or so to develop some sort of immunity to smallpox (at least on the Pacific Coast in *British Columbia), by the time more settlers came along the civilizations had all largely recovered. Well, nearly; some were wiped out, while others, due to the dual pressures of near-extinction and new animals imported from Europe, had gone into overdrive. The history of the peoples of Turtle Island is quite different from that of North America, but there are some glancing similarities...
Starting from the east and moving west, because why not:

In the north of the Eastern Region, bordering the Shield, is the Véstmarr (Norse for "west-lake", as the Baltic Sea is considered the "East-Lake"), not strictly a lake but a cutaway of sorts, a small sea bordering the Atlantic. Small wonder, then, that the Norse took to it so readily, and currently make up most of the inhabitants of the region--with two exceptions. The Mik'maq, who managed to team up with the Greenlandic settlers quite early on, and have taken up an agricultural lifestyle from the Norse while maintaining their own language and a large number of their customs. They, like much of the Shield and a great deal of the Eastern Region, use futhark runes to write their language in. They also farm barley, rye, oats, and apples (among others), and keep chickens, sheep, goats, horses, and cows, all descended from the Icelandic varieties. In fact the Mik'maq and the Norse are the primary source of all of these animals across the continent, from the Véstmarr to the Temperate Rainforest. The other major group in the area, the Innu, are not technically part of the Véstmarr, having a civilization of their own to be part of; still, they're not unwelcome, per se, and do a lot of trading that gets passed down the line into the interior of the continent. A third group, the Beothuk, have not fared so well by comparison, largely disappearing into the background and intermarrying when they have to with Mi'kmaq and Vinlander populations. Vinlandic Norse, similar in many ways to Greenlandic Norse in the north, is the lingua franca of the area. Paganism and Christianity have an odd mix here; folks will attend church willingly, and listen to a version of the Bible that reads more like the Elder Edda, but will still do their best to appease the local spirits around the Véstmarr.
Brjóstland (Anticosti Island) and Vaggaland (Prince Edward Island) are the two major Norse settlements besides Vinland, and benefit greatly from trade with the interior (mainly furs, but these days a lot of copper and iron and wheat as well). The Mi'kmaq have their own lands on the *Gaspé Peninsula (Gespegeoag), in New Brunswick (Sigenigteoag), and in Nova Scotia (from west to east: Gespogoitnag, Segepenegatig, Esgigeoag, Epigoitnag along the northern coast, and Onamag). An Icelandic-style althíngi has been introduced as the primary means of international government; representatives from the Vinlandic and Mi'kmaq chieftainships gather on Vaggaland (also called Pigtogeoag in Mi'kmaq) and make or break laws pertaining to the Norse and Mi'kmaq communities. It's probably the nicest part of the continent, honestly.
Other settlements in this area haven't been quite so harmonious, but, to be fair, they only got there quite recently. With Egypt now under the control of the Abrahamite Empire and Constantinople isolated by the Turks (they turn up everywhere), Europe had to try other ways to get to spices. The Empire of Brythoen, occupying the British Isles, northern Gaul, and (until quite recently) the northern coast of Iberia, was a prime candidate for exploration--as was the newly-separated Alanic kingdom of Rusitana (modern *Portugal), which sought to cut out the middleman in the spice trade, and Vasconia, the Basque Country, broken off from the Brythonic Empire and given the support of the Pope in Rome (as they had chosen to convert to Roman Orthodoxy). So too was the country of Gothe, which started in Toulouse and managed to beat back the Franks through a combination of luck and good choices in allies. The small but prominent Empire of Sardinia, with a relatively Romance language descended from the Italian dialects, also put out a few minor states. The first to cross, Roxihuazga Cavoda (Older Alanic Rawśiwazga Kabawtáa), landed on *Cuba (which he called Boidari, from Middle Persian Bōxtārīh "salvation") in 1382 CE looking for more land to grow crops upon–but that is a story for another time. The second to cross, Morg Endain ab Orod (Marcus Antonius Horatii), crossed and landed in the lands of the Delaware in 1419 CE, where he and his men established a colony, Iwairn Now (New Munster), where later they returned and founded a trading port for furs that slowly developed into a city. The Delaware, for their part, unwittingly accepted the colony, on account of the muskets the colonists carried–something that the iron-wielding Haudenosaunee did not carry. Iwairn Now became the centre of an expanding alliance against the Haudenosaunee, while at the same time, rich furs began making their way back to Brythoen, alongside wheat, quickly a prize crop in the Eastern Region. Euskal Herria's own colony, Legaren Irla on *Long Island (established 1446), stuck around for long enough to leave a Basque-speaking minority before it was subsumed into the Gothian colony of Nuie Duranie (New Dordogne, established 1470), the two merged by decree of Pope Miltiades IX. Both of these colonies have a tendency to buy slaves from both Africa (courtesy of the Zoroastrian empires in the Sahara) and from the locals, although there are still a few Slavic slaves around so it gets...rather confused, at times, as to what precisely it means to be a slave here. Work, sure, but then you get to be free, and then you get to own slaves...
Further southwest and inland a bit lie the Great Lakes, the largest bodies of freshwater on the planet. The major civilization around here is the League of the Longhouse, stretching from the southern edge of Lake Michigan east the St. Laurent, from *Michigan and *New York/Montréal south to *Kentucky and *West Virginia. (There's also a patch of territory occupying the area where *Toronto is in our timeline that's kind of a neutral meeting ground for a great many peoples, League or not.) It was founded, and is currently governed, by the Haudenosaunee, a collection of Northern Iroquoian peoples. Well, I say collection...mostly the Seneca language is used in the west and the Mohawk language in the east, with the Onondaga language being the primary language of government. Derived from the ancient practice of adopting captives in wartime, various tribes are incorporated into the League as "second-class" tribes, bending to the will of the matriarchs of the Eleven Tribes (the Tuscarora, Petun, Huron, Wyandot, and Erie, and Cherokee were given their own council fires after some minor civil wars). The Grand Council, composed of 127 Chiefs divided between the nations and their client states, runs a lot of the show, but there is a second council, the Council of Clan Mothers, that enforces the Iroquoian matrilineal system (and has actually granted power to a lot of women from different cultures under the belt of the Confederacy). These days, they have a tendency to build steppe pyramids for themselves in the major settlements, although the standard longhouse is still prevalent across much of the north. Iron weapons, bought from the Norse, have become commonplace, although still understandably expensive; smithies have opened up all around, and the Chiefs decorate themselves in iron. The League, like the Mi'kmaq, uses a variation of the futhark runes to keep council, although they still use wampum as currency and as a means of marking treaties.
To the south lies the great Mississippi Basin, and assorted pyramid kingdoms thereof. The format is much the same across the basin; great cities at the centre of a farming, fishing, and/or hunting territory, with central mounds containing government structures and individual housing for those individual privileged enough to live there. Livestock has spread, and has been accommodated; the cities were largely depopulated after the end of the Great Plague of the 12th Century, which gave the locals time to readjust to the new agricultural packages and magnify tenfold in population from their post-plague numbers during the next three centuries. Warfare, too, has gone up; bronze-smelting will always be a problem in North America, because of a lack of tin, but thanks to new technologies from the Véstmarr (and increased trade with the Shield and the Great Basin) bronze and iron have also become commonplace. Crime, too, but that's being taken care of via roaming bands of Watchers from the Wild, a post-shamanistic samurai-esque movement dedicated to maintaining a code of honour across the wastelands that never really went away. (These people, besides the most powerful noble families, are normally the only ones allowed to possess horses. They go by many names, and tend make their own weapons–iron swords included.) Writing has become common, but for the most part it's not in futhark runes; instead, the writing, mainly done on pottery or in birch-bark codices, is derived from the Maya script of the Yucatán Peninsula. (More on this later.) As the sounds don't always match up one-to-one, it's common for the basic logograms to remain the same but for additional phonetic glyphs to spell out the word otherwise–or else they simply use Classical Mayan, something which these days is falling out of habit as scribes begin to question the necessity of maintaining connection with such a far-flung civilization.
The Myaamiaki of *Wisconsin, *Illinois, and *Missouri, ancient enemies (by this point) of the Haudenosaunee, have formed a closely-knit civilization under the rule of a Grand Chief centred around the mining of tin from the Upper Mississippi (specifically the Eel River; the Kineepikomeekwaki have become rather popular in this regard). From this tin they make bronze, with which they engage in their endless ritual of trying to win back conquered lands from the Haudenosaunee. The Caddoan Confederacy is a little different; all the tribes in the area are part of a League similar to that of the Haudenosaunee, centred around the city that in OTL is called *Battle Mound, although by far the biggest city is that of *Spiro. It's a surprisingly peaceful place, possibly because they place such an emphasis on trade with other nations. The land known as Hvshi Anowa, the "Path of the Sun", primarily Muskogean in ethnicity, took in a large number of refugees from the collapsed *Fort Ancient civilization when it fell to the Haudenosaunee. It stretches from the southern borders of the League of the Longhouse to the Atlantic, from *Tennessee and the eastern Mississippi to *Georgia and *South Carolina. Curiously, it was nothing particularly political that united their lands, which vary from tribal confederacies to princely states to full-blown theocracies; their worship of Chitokaka, the Great Spirit, as understood through the words of the ishtahullos (those with a certain supernatural bent to them), was what drove them together, and has become quite popular among the other nations of the Eastern Region. (It's also been quite a cautionary point for the various civilizations around them not to try to conquer any of the associated tribes, who have all been "blessed by the Sun" as it were.) *Mobilian Jargon, derived from the Muskogean languages, is one of the more widely-used languages in the Eastern Region, rivalling the Haudenosaunee languages and Vinlandic. *Florida has been divided up between the Timucua to the north (they get along decently with Hvshi Anowa) and the Calusa (they get on much better with the Huasteca). And to the west, in *Louisiana, one finds the Natchez and Taensa, sun-worshippers like Hvshi Anowa (and indeed they use ishtahullos for ceremonies), whose chiefs' palaces are great domes with a central fire burning and, all around, beautifully-woven baskets containing the interred bones of previous chiefs hanging from the ceiling.
One other civilization is worth mentioning in the Eastern Region: the Huasteca Polities, colonies set up by the Maya along the western coast of the Gulf of Mexico. They're not actually all Huastec, or even mostly so; oh, they may have Huasteca citizens, but for the most part they use Yucatán Mayan in their official business, and that's leaking down to the lower classes. They stretch all the way from *Texas down the coast of *Mexico, and each one is its own city-state, with some remains of the bloodlines of the Maya kings in the tribes there. That's not to say that those bloodlines get up to much, to be honest. In order to encourage colonies far from the jungles of home, it was common policy for the Leagues of Yax Mutal (Tikal) and Ox Te' Tuun (Calakmul) to set up some basic rules and regulations to be kept by the common people; these became the basis of what might be considered as pseudo-constitutions, where laws could be set up by prominent figures in society, not necessarily from noble blood, "in lieu of the king's command". In the city of Chik Haal (*Freeport, Texas), originally settled from Yax Mutal, quite a compendium of laws has emerged, based on a compilation of old Maya commandments and recent religious practices borrowed from the Taensa...

[mèþru]

The Great Plague broguht by the Norse should have butterflied away many OTL political organisations among the indigenous peoples. Also, the plague may never have spread that far without a Viking De Soto and European fishermen constantly reinforcing it before colonisation takes off.

I know at least regarding the Iroquoian languages that many had yet to even diverge form each other. Mohawk and Oneida for instance were one language in the 11th century (arguably they never have becme separate languages; the dialect of Mohawk that is the basis of literary Mohawk has high mutual intelligibility with Oneida, but extinct Mohawk dialects had less phonlogical similarities). If you want I can link you a paper on Proto-Iroquoian and its development into both modern and extinct forms of Iroqouian.

[Pedant]

The Great Plague broguht by the Norse should have butterflied away many OTL political organisations among the indigenous peoples. Also, the plague may never have spread that far without a Viking De Soto and European fishermen constantly reinforcing it before colonisation takes off.

Okay, so technically it wasn't a Plague in the sense of the OTL extinction event; barely half of the population ended up dying across the whole of North America. And it spread a lot more slowly because it was animals--cows, horses, goats, sheep, and chickens--that were making their way across the continent from Vínland. Fairly quickly, admittedly (the horse took about a hundred years to spread to the plains), but they still moved, and with that movement came the occasional straggler who'd picked up smallpox in Vinland. On the other hand, increasing presence of livestock did wonders for the immune systems of those who had to live with them. But it was definitely a plague for the Mississippians; civilization went through a temporary collapse, leading to the Haudenosaunee taking a lot of territory to the north and the foundation of the Watchers from the Wilds (who were messengers in the old days, and tended to ride horses--think something like North American samurai without any particular king to be bound to). It also led to the popularization of the sun-religion of the south, in the hopes that somebody would listen to their pleas and keep them alive. So, by the time Europeans actually come to the continent again (the Vinlanders not completely counting by this point), they'd be facing cultures that were a little more pockmarked, a little more cautious, a little more condensed, and with quite a few more legs-up than their contemporaries (like livestock and hieroglyphs).
Around the 14th Century a Mayan healer discovered that powdered pustules rubbed against scratches in the skin led to a milder version of the disease that resolved itself in about two to four weeks, but that's a story for another time.

I know at least regarding the Iroquoian languages that many had yet to even diverge form each other. Mohawk and Oneida for instance were one language in the 11th century (arguably they never have becme separate languages; the dialect of Mohawk that is the basis of literary Mohawk has high mutual intelligibility with Oneida, but extinct Mohawk dialects had less phonlogical similarities). If you want I can link you a paper on Proto-Iroquoian and its development into both modern and extinct forms of Iroqouian.

...see, this is exactly the kind of information that I really did try hard to find out but couldn't actually locate. I found a ruddy paper of Proto-Muskogean, for crying out loud, but not one on Proto-Algonquian. So, well, yes, I should be most grateful indeed.

EDIT: I meant Proto-Iroquoian, I meant Proto-Iroquoian...

[cedh]

This scenario looks very interesting, I'm looking forward to more!

...see, this is exactly the kind of information that I really did try hard to find out but couldn't actually locate. I found a ruddy paper of Proto-Muskogean, for crying out loud, but not one on Proto-Algonquian. So, well, yes, I should be most grateful indeed.

Thanks to Whimemsz and a few other ZBBers, a good starting point for resources on Proto-Algonquian is this post and following. See also this and this.

[Pedant]

This scenario looks very interesting, I'm looking forward to more!

...see, this is exactly the kind of information that I really did try hard to find out but couldn't actually locate. I found a ruddy paper of Proto-Muskogean, for crying out loud, but not one on Proto-Algonquian. So, well, yes, I should be most grateful indeed.

Thanks to Whimemsz and a few other ZBBers, a good starting point for resources on Proto-Algonquian is this post and following. See also this and this.

Bellissimo! Thanks, cedh!

[Whimemsz]

.

[Salmoneus]

I don't mean to poke holes, particularly as I don't think you're aiming for strict realism here.

But I don't think smallpox works that way. Smallpox is actually quite difficult to spread, and very difficult to have become endemic. It spreads slowly and inefficiently.



First, smallpox cannot be spread by 'animals making their way across the continent' - smallpox can virtually only be spread by direct, human-to-human contact. [this is also why it was easy to eradicate - unlike diseases like flu or ebola, there is no reservoir for smallpox in the animal population]. Very close contact, in fact - although there are a few cases of infection from spending time in very close quarters with the infected with poor ventilation, it's mostly spread by breath. You normally have to be within a few feet of the infected (usually, apparently, within ten inches) - infections are also known from contact with things the infected have touched (like clothes) and their bodily fluids, but these aren't very common, and have a very limited window (unlike some pathogens, smallpox doesn't survive long outside the body).

Second, once you've had smallpox, you stop being contagious. There are no asymptomatic 'carriers' of the disease - so it doesn't matter how many people you touch, it's only how many people you touch while you actually have active smallpox that matters.

Third, you're only contagious for a brief period - a couple of weeks, and almost all the contagiousness takes place within about a week.

Fourth, you're not likely to spread it to many people while you're infected, because you feel very ill, are rapidly bedridden, and are covered in horribly disfiguring pustules.

Fifth, if you survive, you're now immune to smallpox - you can't get it twice. [well, I'm sure it's happened, but...]


What this means is that smallpox isn't a disease that can be spread by a rogue horse, or even a stray horse-trader - one guy with smallpox coming to a non-immune community might kill a few, or even dozens, but outbreaks very quickly die out - it's not long before everyone is either dead, immune, or wisely absent from the area. A good example of this is the fact that smallpox never became endemic in Australia or New Zealand, even in the 20th century, so they never actually had to introduce the smallpox vaccine - a few outbreaks occured, but they quickly died out.

Now, from this you might think that smallpox itself would rapidly die out. A good guess. It can only survive when: a) there are a lot of people infected at one time (which makes it hard to avoid them), and b) those people live within a much, much larger population of uninfected. Because smallpox, as it were, burns its bridges - it leaves people either dead or immune and needs to be constantly transmitted to never-yet-infected people to survive - it needs to have so many people in the population that it can continue infecting people until a new generation has arrived for it to infect. Smallpox occurs in booms, huge outbreaks that infect and kill lots, when immunity is low - and that then die back as the number of fresh victims to infect declines; but if the population is below the threshold, then there aren't enough people to infect to tide the virus over in the lean times, and the virus does indeed die out in that population. [conversely, because in a large population the virus is 'fed' every few by a new crop of unimmune children, outbreaks occur 'too soon', when most people are still immune from last time, and therefore you don't see the cataclysmic pandemics you get when it enters a new area - in europe in the early modern period, smallpox killed less than 10% of the population each decade (a bit under 10% of all European deaths on average, peaking at up to 20% in some places in epidemics). FWIW, smallpox outbreaks occured every 2-4 years]

I can't actually find a figure for the threshold population of smallpox (and of course it's not easy to define, since it's really about density and connectedness), but it must be at least the high hundreds of thousands, if not the millions, in a relatively small area. For measles, it's said that the threshold population is about 500,000, but measles is a much more dangerous disease than smallpox, in terms of infectiousness.


Notably, this is why smallpox was not endemic in Europe between the fall of Rome and the late middle ages - it was sporadically reintroduced from the middle east, but the epidemics simply died out, because Europe was too rural to support the disease. Only when there was massive reintroduction from the middle east via the returning crusaders, and when those crusaders returned to a more densely populated and urban society than in previous centuries, did smallpox become endemic (ironically, it probably didn't really become ubiquitous in Europe until around the 15th century, just in time to infect the new world).

--------------------


So I think three things should be pointed out:

a) it seems unlikely that some Vikings on Newfoundland would really be able to spread smallpox across North America, given the low population density - the people they infected would probably become bedbound before they were able to pass it on; the entire pre-Columbian population of Newfoundland is estimated in the hundreds, spread out across a big area;

b) if they did spread smallpox to more than just the neighbouring tribe, the population north of Mexico was so small and so thinly dispersed that it almost certainly could not have become endemic - there just wasn't the sort of densely-packed urban, agricultural society that smallpox requires;

c) without endemicising, an early exposure to smallpox probably wouldn't have helped. There's no actual evidence of ANY genetic immunity to smallpox ever having developed anywhere, and indeed well into the 20th century the most smallpox-ridden area, India, was the area with arguably the longest history of smallpox. It is hypothesised, simply from looking at different rates of infection in, for example, New Zealand (i.e. europeans vs maori) that there was SOME genetic resilience, but it clearly wasn't very great, and its very existence is conjectural (it may just be that the maori had less understanding of smallpox and how to avoid it, lower levels of health and nutrition to make them more susceptible to any disease, and worse medical care available - we know that income was highly correlated with smallpox in th 20th century, both between and within countries, so it can't all be blamed on genes*);

d) the above is a little superfluous, because the Vikings didn't have smallpox, and hence couldn't have transmitted it. Smallpox didn't reach Iceland until th 13th century, and didn't become endemic there for hundreds of years, if ever (the population was too small). Even if there had been smallpox in Iceland, it wouldn't have made it to the west - Vinland was settled from Greenland, which never had more than a few thousand settlers (only a few hundred on the west, from where Vinland was settled).

e) if the native americans had indeed survived smallpox, they'd still have been eradicated by measles, which arrived in Europe even later than smallpox.


--------------------


Anyway, sorry to sound so negative. Hopefully even if you choose to stick with your original plan, the above may be of interest to others in terms of thinking about disease in conworlds and alt-histories...


*I originally typoed "gnes", and was SO tempted to 'correct' it to "gnus"...

[Pedant]

I don't mean to poke holes, particularly as I don't think you're aiming for strict realism here.
But I don't think smallpox works that way. Smallpox is actually quite difficult to spread, and very difficult to have become endemic. It spreads slowly and inefficiently.

First, smallpox cannot be spread by 'animals making their way across the continent' - smallpox can virtually only be spread by direct, human-to-human contact. [this is also why it was easy to eradicate - unlike diseases like flu or ebola, there is no reservoir for smallpox in the animal population]. Very close contact, in fact - although there are a few cases of infection from spending time in very close quarters with the infected with poor ventilation, it's mostly spread by breath. You normally have to be within a few feet of the infected (usually, apparently, within ten inches) - infections are also known from contact with things the infected have touched (like clothes) and their bodily fluids, but these aren't very common, and have a very limited window (unlike some pathogens, smallpox doesn't survive long outside the body).
Second, once you've had smallpox, you stop being contagious. There are no asymptomatic 'carriers' of the disease - so it doesn't matter how many people you touch, it's only how many people you touch while you actually have active smallpox that matters.
Third, you're only contagious for a brief period - a couple of weeks, and almost all the contagiousness takes place within about a week.
Fourth, you're not likely to spread it to many people while you're infected, because you feel very ill, are rapidly bedridden, and are covered in horribly disfiguring pustules.
Fifth, if you survive, you're now immune to smallpox - you can't get it twice. [well, I'm sure it's happened, but...]

What this means is that smallpox isn't a disease that can be spread by a rogue horse, or even a stray horse-trader - one guy with smallpox coming to a non-immune community might kill a few, or even dozens, but outbreaks very quickly die out - it's not long before everyone is either dead, immune, or wisely absent from the area. A good example of this is the fact that smallpox never became endemic in Australia or New Zealand, even in the 20th century, so they never actually had to introduce the smallpox vaccine - a few outbreaks occured, but they quickly died out.
Now, from this you might think that smallpox itself would rapidly die out. A good guess. It can only survive when: a) there are a lot of people infected at one time (which makes it hard to avoid them), and b) those people live within a much, much larger population of uninfected. Because smallpox, as it were, burns its bridges - it leaves people either dead or immune and needs to be constantly transmitted to never-yet-infected people to survive - it needs to have so many people in the population that it can continue infecting people until a new generation has arrived for it to infect. Smallpox occurs in booms, huge outbreaks that infect and kill lots, when immunity is low - and that then die back as the number of fresh victims to infect declines; but if the population is below the threshold, then there aren't enough people to infect to tide the virus over in the lean times, and the virus does indeed die out in that population. [conversely, because in a large population the virus is 'fed' every few by a new crop of unimmune children, outbreaks occur 'too soon', when most people are still immune from last time, and therefore you don't see the cataclysmic pandemics you get when it enters a new area - in europe in the early modern period, smallpox killed less than 10% of the population each decade (a bit under 10% of all European deaths on average, peaking at up to 20% in some places in epidemics). FWIW, smallpox outbreaks occured every 2-4 years]
I can't actually find a figure for the threshold population of smallpox (and of course it's not easy to define, since it's really about density and connectedness), but it must be at least the high hundreds of thousands, if not the millions, in a relatively small area. For measles, it's said that the threshold population is about 500,000, but measles is a much more dangerous disease than smallpox, in terms of infectiousness.

Notably, this is why smallpox was not endemic in Europe between the fall of Rome and the late middle ages - it was sporadically reintroduced from the middle east, but the epidemics simply died out, because Europe was too rural to support the disease. Only when there was massive reintroduction from the middle east via the returning crusaders, and when those crusaders returned to a more densely populated and urban society than in previous centuries, did smallpox become endemic (ironically, it probably didn't really become ubiquitous in Europe until around the 15th century, just in time to infect the new world).

--------------------

So I think three things should be pointed out:
a) it seems unlikely that some Vikings on Newfoundland would really be able to spread smallpox across North America, given the low population density - the people they infected would probably become bed-bound before they were able to pass it on; the entire pre-Columbian population of Newfoundland is estimated in the hundreds, spread out across a big area;
b) if they did spread smallpox to more than just the neighbouring tribe, the population north of Mexico was so small and so thinly dispersed that it almost certainly could not have become endemic - there just wasn't the sort of densely-packed urban, agricultural society that smallpox requires;
c) without endemicising, an early exposure to smallpox probably wouldn't have helped. There's no actual evidence of ANY genetic immunity to smallpox ever having developed anywhere, and indeed well into the 20th century the most smallpox-ridden area, India, was the area with arguably the longest history of smallpox. It is hypothesized, simply from looking at different rates of infection in, for example, New Zealand (i.e. europeans vs maori) that there was SOME genetic resilience, but it clearly wasn't very great, and its very existence is conjectural (it may just be that the maori had less understanding of smallpox and how to avoid it, lower levels of health and nutrition to make them more susceptible to any disease, and worse medical care available - we know that income was highly correlated with smallpox in the 20th century, both between and within countries, so it can't all be blamed on genes*);
d) the above is a little superfluous, because the Vikings didn't have smallpox, and hence couldn't have transmitted it. Smallpox didn't reach Iceland until th 13th century, and didn't become endemic there for hundreds of years, if ever (the population was too small). Even if there had been smallpox in Iceland, it wouldn't have made it to the west - Vinland was settled from Greenland, which never had more than a few thousand settlers (only a few hundred on the west, from where Vinland was settled).
e) if the native americans had indeed survived smallpox, they'd still have been eradicated by measles, which arrived in Europe even later than smallpox.

--------------------

Anyway, sorry to sound so negative. Hopefully even if you choose to stick with your original plan, the above may be of interest to others in terms of thinking about disease in conworlds and alt-histories...

*I originally typoed "gnes", and was SO tempted to 'correct' it to "gnus"...

...well, that's given me a lot to think about.
Alright, new information taken into account and I have a few possible scenarios in mind. The first being that spreading cows across the continent might help in terms of cowpox rather than smallpox (which was the primary bit of reading I had in mind when working out this scenario, cowpox leaving one less susceptible if not immune to smallpox), but that settlement only came along later. The Brythons and Goths and Basque might have potentially introduced something in North America, or the Rusitanians in the Caribbean, but then that'd be a century later. So...maybe I could have something else work out differently in this timeline? My hope was that the introduction of livestock would also serve to group communities together better, maybe increase population density a tad (especially around the Mississippi River Basin), which might hypothetically provide a sufficient number of closely-knit people for the disease to become endemic. I'd also been trying to adjust things so that the colder temperatures of the Little Ice Age took place a bit earlier (say about nine hundred years ahead of schedule), leading to more tightly-packed communities and a greater turn towards agriculture. This may be enough; this may not be. As to measles...well, that's going to be a tad more difficult. I'll think of something.
Actually, there is another alternative. If the Crusades themselves weren't quite as strong (on account of there being three Roman Empires at this point, none of whom actually believe the other to be the proper empire--and this has been the case for about a thousand years at this point), then there wouldn't have been the massive flux of people in and out. No smallpox epidemic to attack Europe, no smallpox outbreak to attack the Americas. Maybe measles can develop from cattle-using civilizations over in the Western Hemisphere instead, their own particular breed of rinderpest going nuts and setting civilization back a bit before it regroups stronger than ever (and possibly infects Europeans coming over)...
(Of course, for that I suppose I'd need to know a bit more about disease control, or else try and create a new disease entirely. Both possible!)
I'm legitimately asking for advice here. The point of divergence is in the year 400 CE, after all, there may be one or two things that can work out a bit better (or worse). Maybe not complete realism, but as close as I can get in as many areas as I can get.

[Neon Fox]

No smallpox epidemic to attack Europe, no smallpox outbreak to attack the Americas. Maybe measles can develop from cattle-using civilizations over in the Western Hemisphere instead, their own particular breed of rinderpest going nuts and setting civilization back a bit before it regroups stronger than ever (and possibly infects Europeans coming over)...

A thing to know about measles: it can screw with the immune system, rendering sufferers more likely to get other infections for weeks to months after.

[dhok]

Measles, it's worth noting, doesn't seem to have really jumped to humans (to the point of becoming endemic) until about 1100-1200 AD.

Of course, that can be move back a few centuries.

[Pedant]

Measles, it's worth noting, doesn't seem to have really jumped to humans (to the point of becoming endemic) until about 1100-1200 AD.

Of course, that can be move back a few centuries.

In this case it’s right on time; by that point in TTL the New Worlders had cattle, all the better to get cowpox and measles from...

A thing to know about measles: it can screw with the immune system, rendering sufferers more likely to get other infections for weeks to months after.

Hmm...I need to do some more reading on New World and livestock-derived diseases...hey, maybe I could give them chicken pox, too! Okay, this is definitely putting a dent in the population, but with a bit of luck it won’t be enough to kill off everyone...

[dhok]

One alternate history I saw a couple years ago was predicated on Carthage winning the Punic Wars, and engaging in small-scale colonization of northeastern Brazil and the US.

I think the real variable here is time--how many centuries do the Americas have to prepare?--plus a colonizing/contacting power that is too small and weak to take advantage of the situation (like Norway or Carthage, but unlike Portugal or Spain).

[Pedant]

One alternate history I saw a couple years ago was predicated on Carthage winning the Punic Wars, and engaging in small-scale colonization of northeastern Brazil and the US.

I think the real variable here is time--how many centuries do the Americas have to prepare?--plus a colonizing/contacting power that is too small and weak to take advantage of the situation (like Norway or Carthage, but unlike Portugal or Spain).

The good folks of the Americas now have five hundred years to prepare, plus much weaker colonizing powers due to Buddhists (which the Turks became in this reality, as opposed to Muslims because the Arabian Peninsula converted to Judaism around the late 7th Century and has stayed that way ever since) being a bit more tolerant of travelling spice merchants. They have to deal with Brythoen (alias the Western Roman Empire, thanks to Constantine III being compelled by bad weather and a lucky escape from a Germanic raid to fortify the home islands first), Gothe (which takes up maybe half of France, the other half being Brythonic; very Roman Orthodox), Rusitana (Alanic in origin, and only recently converted to Christianity), as well as the hardy but small-in-number Vinlanders (they were the first), Euskal Herria (cutting into the territory of Gothe and Rusitana by taking the swathes of Northern Iberia that the Brythons didn’t take), and Sardinia (mixed Zoroastrian and Roman Orthodox, with no particular animosity, archipelago empire wanting a direct link to the spice trade for the Papacy). Of these, Brythoen is probably the strongest, but it’s hindered somewhat by the fact that guns are moving about a century later than they did in our world--in other words, not until after the first Brythonic colony was founded did hand-held cannons arrive in Brythoen. The others are hampered by lack of seafaring expertise, lack of firepower, lack of manifest destiny-style incentive, lack of we’ve-been-cut-off-from-spices-style incentive, or a combination thereof.

[mèþru]

The point of divergence is in the year 400 CE

If it is that early then the world would probably be much more different than you depicted. I'd go all the way back and develop it step by step from 400 CE.

Here's the Proto-Iroquoian paper: http://mspace.lib.umanitoba.ca/bitstrea ... sequence=1

[Pedant]

The point of divergence is in the year 400 CE

If it is that early then the world would probably be much more different than you depicted. I'd go all the way back and develop it step by step from 400 CE.

Here's the Proto-Iroquoian paper: http://mspace.lib.umanitoba.ca/bitstrea ... sequence=1

This I am in the process of doing...
And many thanks indeed!

[Pedant]

At the suggestion of mèþru, perhaps it'd be reasonable to explore all of the potential changes across the world. The current year in the Blessed Cold universe is 1500 CE, and the Point of Divergence is in 400 CE. Looking at the world over the course of a hundred years at a time, this gives me eleven centuries within which to work--and to post timelines listing some of the changes. So, without further ado, here's the Blessed Cold: 400-500 CE:
(NOTE: this is most definitely not yet complete. Hopefully one day it will be.)

	400-24	425-449	450-474	475-499
Europe and Central Asia	405: massive storms in the *British Isles, the *Netherlands, *Germany, and *Denmark causes great loss of life. 408: failed raid of the British Isles from the Angles and Saxons (among others), due to a massive storm that wipes out most of their fleet. 409: Emperor Honorius declares Constantine as Constantine III, co-emperor of the Western Empire. Constantine II’s armies are called back to Gaul to help stop a Vandal attack, stronger in force than in OTL; they are aided by the forces of General Gerontius, who dies on the battlefield. Second failed raid of the Islands; granted, this time the Angles and Saxons get somewhere, but Constantine II’s forces are able to prevent more than minor damage, earning him the respect of the people. 410: -Constantine II, faced with the choice of the Western Empire generally and the British Islands specifically, returns to Britain to shore up defences against the Irish and Saxons both with as many troops as is possible; he meets with various tribal leaders and convenes a Senate (Henad in British Latin) of chiefs and military officers, in London, from which to set up a base of operations. Constantinus and his son Constans become the new Augustus and Caesar (Oedd and Coedd in modern terminology) of the Britannic Empire. -Rome is sacked (yet again). 421: Julianus I ascends the throne of Britannia as Augustus when his father, Constantine II, dies.	431: Gratian I becomes Caesar, ruling alongside his father Julianus. There is a brief but insubstantial war with the kingdom of Dumnonia in the southwest of Great Britain, which ends in a stalemate (largely because the Roman troops couldn't afford to lose the fort nearby, Isca Dumnonium). 436: Gratian I transitions from Caesar to Augustus after the death of his father Julianus. 447: the Alans, getting in on the gig, sack the city of Rome. 449: Theoderic I of the Visigoths dies.	451: -Constans III ascends the throne of the Britannic Empire as full Augustus after the death of his father. -The Council of Chalcedon takes place--and in the process (perhaps under scrutiny from outside forces) miaphytism (the belief that Jesus' human and divine natures were mixed together as one) becomes the dominant belief in the Eastern Empire. Followers of dyophitism (Jesus' human and divine natures existed separately in his form, but perfectly balanced) are excommunicated--unfortunately including the (now discredited) Pope in Rome, whose lands have largely fallen to Arian Christians in any case.	499: -Artorius is born to Ultor/Wthyr. -the Battle of Poitiers: Alaric III of the Visigoths kills Wīgarāt (“warlike counsel”) of the Franks, driving them back to a very specific area of France and the Netherlands and securing Gothic supremacy over the lands from Tarragona to Monaco, from La Rochelle to Geneva and Strasbourg.
Middle East and North Africa	420: the Alans get as far along as Carthage before stopping and establishing their territory.
Sub-Saharan Africa	400s: settlers from *Borneo begin to colonize *Madagascar.
South Asia	412: Chandragupta II of the Gupta Empire dies; his son, Kumaragupta I, takes the throne.
East Asia	400: The Samalas Volcano erupts on Lombok Island, triggering what historians will call the Little Ice Age. 420: Lɨu YɨoH (劉裕) founds the Song Dynasty in southern China. 422: after Lɨu YɨoH proves himself relatively incompetent (as does his first son), his second son takes the throne and the imperial name Mɨun (文). He turns out to be a relatively careful and frugal leader. 423: the Wei Dynasty builds their own variation of the Great Wall, 2500 li (1,350km) long.	430: Emperor Mɨun of the Song Dynasty retakes cities captured from his brother by the Northern Wei Dynasty--then, during the winter, crosses the river into Wei lands to capture their cities. 430: the ThɑiHmɨoX Emperor of the Wei is killed in combat against Mɨun of the Song; his territory is taken up by the Song. 432: the Hˠæk̚liᴇn emperor DeŋH of the Xia dies as his capital is besieged by Mɨun's forces; the kingdom of Xia is incorporated into Song lands along with Wei territory.	464: five monks from Gandhara travel up the Silk Road and land (in spite of a massive storm) in Japan, spreading Buddhism in the court of the Emperor Yūryaku. 465: Emperor Mɨun dies of natural causes; his son Lɨu DʑiᴇuH takes the throne.	482: Emperor Lɨu DʑiᴇuH dies; his son Lɨu ɦʉiXTɕɨ takes over as Emperor of the Song.
Oceania
North America
Central America	410: the Highland Maya fall to the control of the northern city of Teotihuacan.	426: Copán is founded in the southeast by the legendary figure K’inich Yax K’uk’ Mo’.
South America
World

[Ares Land]

Very interesting, and I'm looking forward to reading more about it.

One thing I don't quite get is why Britain is so important at this stage in your timeline? My knowledge of that period is really hazy, but weren't the British Isles a backwater at this point in history?