https://www.amazon.com/Dark-Secrets-SHTF-Survival-Violence/dp/1792159226

A Norse prince united the greater Norse world behind a sort of neo asgardian religion with overtones of druidism, hinduism and confucianism to defend wisdom and learning, a little bit against more trad pagans but mostly against horrid obscurantist Christianity. Eventually, his chief foe is a Holy Roman Empire soldier who possesses the holy lance.

Harrison’s approach to the issues at play in the tenth century is idiosyncratic to say the least, and one definitely gets the message he really didn’t like Christianity, but the books were great yarns.

It’s just that his purported new religion is one of the most unlikely historical contrivances I’ve ever seen. No time traveller though- that would have made it more plausible.

I early gravitated more to stories in which the timeline was being protected at all costs- from the clever silliness of Simon Hawke’s Timewars series to the more serious tales of the Time Patrol by Poul Anderson. I still think the latter’s Delenda Est and The Sorrows of Odin the Goth were quite poignant.

It is on Youtube of you are interested:

https://www.youtube.com/results?search_query=goodnight+sweetheart

OK, great–You have your time travel, and you somehow manage to make the tech work. Now what? How are those technologies going to resonate through the social commons?

Consider the car, as an example: We have a real-world example of cultural adaptation in Asia, with the way the car was taken up as a mass-market item in countries like Korea during the late 1980s and early ’90s. Even with the example of the rest of the developed world having had widespread civilian use of the automobile, that whole process in Korea was not at all pretty, nor was it easy. The traffic laws alone… Sweet baby babbling Jesus…

I remember one event, where I was on a US Army shuttle bus on a highway between Kimpo Airport and downtown Seoul. Korean civilian driver merged into the side of the bus. Response? In the middle of traffic on a six-lane highway, both the bus and the car stopped, the police came, and they left the bus and the car sitting in the middle of the ‘effing highway! Waiting for “accident investigations” to show up… Meanwhile, traffic is going by on either side of us at 60mph, both drivers are arrested and taken away, and the passengers of both vehicles are sitting there going “WTF do we do, now…?”.

The technology is relatively simple. The societal adaptations and uptake ain’t.

We have a model for how things go, but try to imagine handing off fully-realized cell phone technology to, say, Americans of the 1830s, who’d no exposure to even the telegraph. Care to imagine the initial ramifications, then the second- and third-order effects?

There’s probably stuff we haven’t even imagined, that the people of that period would find shocking. We got to cell phones relatively slowly, with plenty of time to adapt social mores and values. Same with the rest of the world–Even in deepest, darkest primitive nations where they never had landlines, they at least had exposure to the idea of telephony, and the cell is just a relatively obvious outgrowth of what they’d likely seen in movies and other cultural “stuff” from the first world. Try to imagine what a “first exposure” to that technology would look like, with no prior or parallel cultural adaptation to look at, a true “tabula rasa” deployment.

Now, imagine an imperative where you have to have the technology taken up by the society you need to “update” for some existential crisis. The whole thing would be a hell of a lot more complicated and difficult than you’d think.

Hell, imagine the implications for having foreknowledge of the general run of history, and trying to effect a change to it all. “Hey, Poland of the 1100s… In about a hundred years, the Mongols (who you know nothing about…) are gonna roll through here and wreck the place… Here’s what we need to do to get ready for that…”.

Frankowski did a major Mary-Sue series on just that premise, called the Cross-Time Engineer, but I think he really outrageously underestimated the whole thing in the name of story-telling. Something as simple as taking 10th Century Poland to a state where the Mongols would have bounced off their frontiers is an exercise fraught with complexities that I don’t think he even imagined, and I seriously doubt that even “jump-grading” England of the 1930s by a few decades would be any easier. Or, more historically plausible.

For an early, relatively plausible take, Lest Darkness Fall is good.

The social and political convincing is always important, unless you luck out and travel with a whole community, fully kitted out and able to immediately demonstrate value to the downtime audience. Or conquer them. Mark Twain was a pioneer in recognizing some of the problems.

Turtledove’s Guns of the South showed another problem. I am not myself entirely convinced of the political implications of his ending, but he’d hardly get that published today.

Kirk, damnit, I had a similar notion a few years back. But I suppose it’s just a another take on time-engineering going wrong aka “Guns of The South.” Would make a good short story….

Agreed. If you are believed by the powers that be, there’s no story. France and Britain invade Germany and depose Hitler in 1934 without significant resistance.

Jump-starting tech is a fun conceit, but as Kirk said, it’s a uni-dimensional military history take on the situation: the sort of people who think amazing new technical capabilities can be summoned into existence at the drop of a hat. It shows a real ignorance of economic and technical and cultural and organisational constraints.

What effects that has on history is pure speculation. What does Stalin do when there is no German (Nazi) war?