Sorry, noticed this a bit late, but am curious:
By what measure are you saying the Norse who reached Vinland weren’t vikings? By any current interpretation of the the term, they were definitely vikings.
They weren’t raiding the locals. They came to settle. They brought along women and livestock, built houses, etc. They would have been happy to get along with the locals, trading with them, etc. But people are people and do stupid stuff. Like killing some locals who were just napping under their boats.
The same applies to any hypothetical return journey by Old World folks. And I’d think a big oceangoing canoe would be less at the mercy of trade winds. Anyway my point was about the framing of the question.
To “go viking” was to set out on a raid. As **ftg **sez.
But yeah, people call the Norse during that period- “Vikings”, i was just being pedantic.
Current thought is that *go viking *could originally mean just “go on a sea voyage” just as much as “go violently raiding”, based on variant etymologies.
Most of the pre-Columbian African contact theories basically postulate a one-way voyage with people being assimilated. The issue is which way is easier to make that initial voyage, either on purpose or by accident. Follow-up and return voyages are easier once you’ve made that initial trip. Supposedly (I’m not a fan of the Africa->South America theories, in any case)
The same forces affect thesurface currents as well.
I think it’s because the 2 known contacts were both Westwards.
In the vein of speculation about one way trips from the Ancient Old World to the Americas, I remember reading/seeing something about the discovery of an Ancient Roman ship with a cargo of amphorae, sculptures, coins with Emperors on them, etc., in a South American harbor.
I would have read this in high school in the mid-1980s, in what I remembered as being the NY Times, not the Weekly World News.
I found it odd that I never read any more details either debunking it or exploring it further. Then I forgot about it, assuming it was a hoax that simply faded from discussion. I like a good hoax exposé and they usually make the news, but maybe this one just got killed so quickly there was no pre-Internet hoopla about it (in contrast to, say, the Hitler Diaries).
Well recently, while watching some cheesy conspiracy themed show for late night fun, I saw this mentioned as a potential government cover-up, “for unknown reasons” (cue ominous and unsettling music). And the show had an image of the NY Times article headline! Two of them!
Rio Artifacts May Indicate Roman Visit (NYT, Oct 10, 1982)
Underwater Exploring Is Banned In Brazil (NYT, June 25, 1985)
I don’t trust a current Google search on this topic, which is dominated by “open user discussion and up voting” type results on Reddit or Quora, or plenty of clearly conspiracy or speculation driven websites.
So I turn to the SDMB for the Straight Dope 
IIRC Columbus mentions a small boat found drifting near Iceland that contained the bodies of two people of unknown race. It is speculated that these could have been Inuit or other Native Americans that drifted across the Atlantic. But they didn’t make it alive.
As for the more general question, if a mysterious canoe bearing people of strange race speaking an unknown language reached the European mainland it most likely would be a matter of historical record. Advanced civilizations mostly didn’t develop in the New World until after the invention of writing.
As mentioned, the presence of the sweet potato in Polynesia indicates some kind of contact with South America. Whether this was due to a one-way voyage from South America or a two-way trip by the Polynesians is uncertain.
If they’d shown up in Spain or France, for sure there would be a record. Somewhere in West Africa? Maybe not, especially if it were a one off. I’m not arguing that it happened, just suggesting that it could have. The Polynesians, as you say, made long voyages without having the kind of developed technological society that made European exploration possible.
There’s a very good exhibit (or there was, when I saw it 20 years ago) in the museum in Victoria about the 1860’s smallpox epidemic among the Northwest Coast tribes. Generally it seems a canoe-load of locals would visit a trading post like Victoria and head home carrying the infection. Some died on the way - one newspaper article described some children from Vitoria who found a group dying and dead in the forest; they’d put ashore for shelter after taking sick on the way up the coast.
A book I read on the Alaskan epidemic in the 1890’s found that the survival rate for Alaskan natives was about the same as for Europeans - if they had care, such as an immune person or a missionary. The massive death toll that most native communities experiences was not from smallpox itself, but because with absolutely everyone deliriously sick at once, death was mainly due to starvation, dehydration, and exposure. A little care made all the difference. Plus, in subsistence communities, it’s not like they can draw water from a tap or go to the fridge for a quick meal.
And to add to the point - this happened in waves. Centuries after de Soto and his pet pigs allegedly wiped out the Mound Builders (debateable) we still hear stories of natives near Detroit or on the plains allegedly being deliberately infected with smallpox by white men - so the disease was nowhere near as widespread as we seem to think, or it would be no worse to locals than to Europeans.
More likely, the fact is that on first contact, the disease would not travel very easily over distance and geographic barriers - and followed the same pattern we saw with bubonic plague after 1350 or thanks to anti-vaxxers today - A disease spreads until everyone is either immune or dead. Then, as the number of immune decline over time and new populations are not immune, a sudden critical mass of those can cause another opportunistic outbreak.
So it’s not like the majority of North America’s inhabitants suddenly died as soon as the Spanish landed; in fact, it appears that waves of disease spread outward as each European encroachment encountered a new geographical pocket of population. As mentioned above, the extent of damage depended on the population density.
That tale was reported by Columbus’s son Ferdinand in his biography of his father. Supposedly happened in 1477 in Ireland.
Without a sail, crossing the Atlantic in those days wasn’t really healthy for you. OTOH, I recall a post-contact incident of some guys in a small boat making it to Northern Europe after being driven across the ocean by a storm and being rescued alive. Thought at the time to be Asian but more likely Indian. Can’t find a link at the moment.
The North and South Equatorial Currents both run from east to west and would make a voyage directly eastward from the Americas to Africa nearly impossible. The prevailing currents, in particular the Gulf Stream, would bring any voyagers first to European waters. (Eventually the currents bend southward again towards North Africa, but having enough supplies to survive such a lengthy voyage would be even less likely than reaching Europe.)
Which brings up another issue: having enough fresh water and food to survive a voyage. European voyagers were prepared for voyages of months, and tried to have enough supplies and water aboard - and even then, having food and water give out or go bad was a constant risk. Likewise, the Polynesians were prepared for lengthy voyages. In the Americas, sea travel was mostly coastal, so any vessels wouldn’t have had sufficient stores of food or water for an Atlantic crossing. With great good luck survival on fish and rain water en route could have been possible, though the odds would be against it.
Thanks. I thought it was probably in Ferdinand’s account but couldn’t find the passage. I misremembered that it was Iceland instead of Ireland. (Columbus says he visited a place called Thule that may have been Iceland, although this is somewhat controversial.)
Thanks for the current info, that makes sense.
While the sweet potato [Ipomoea] has been seen as a possible human transplant from South America into the Pacific as part of the Polynesian expansion, there is recent research suggesting that the Pacific and South American strains diverged before this took place. Needs more work but there is a plausible non-human explanation emerging.
The Case of The Chilean Chickens also had us het up for a while, with the possibility that South American chickens had a distinct Polynesian pre-Columbian ancestry. It was an incredibly plausible case apart from the minor detail of no evidence, and contrary results once someone looked.
A reference to the various post-contact stories of Inuit washing up in the north of Scotland?
I don’t think so, but there are some interesting reports. Googling on the the term “Finn-men” for (probably) Inuit’s seen near Scotland at least from the 1600s. A bit more historical text on them here.
Note that the ancestral Thule people didn’t reach S. Greenland until late in the Norse Greenland settlement period. Maybe the earlier Dorset people didn’t have the seagoing tech to reach Scotland.
Of course, washing up dead on a far coast might be evidence of that lack of seagoing tech.
Whether the vikings introduced disease to North American natives isn’t known, but is a possibility. The Dorset culture of northeastern Canada disappeared between the time the Norse arrived in North America and the time they disappeared from Greenland. No one knows why, but disease introduced by the Norse remains possible. On the other hand, the Norse as well as the Dorset were replaced by the Thule, who are still around in the area now.
But it’s unlikely there was any regular contact between Alaskan natives and natives of the Russian Far East before Russians arrived in the area in the late 17th century. There’s no evidence for it, and the islands in the relevant chain closest to Russia were uninhabited until the arrival of the Russians as well.
Per the maps in my link, the Dorset people lived surprisingly far north, so the onset of the Little Ice Age would have really done a number on them regardless of European diseases.
I knew that there were Aleuts living in both the US and Russian Aleutian Islands. Checking I see that the Aleuts on the Russian Commander Islands were brought there by the Russians in the 1800s. So not nearly as ancient as I thought.