AFTERWORD
FOR NERDS LIKE ME:
CONCERNING TECHNOLOGICAL
INNOVATIONS AND TIME TRAVEL
Travelers from the future bringing inventions to the past are a staple trope of science fiction. To Turn the Tide continues that grand old tradition. Bear in mind that this is a well-read amateur writing, not a professional historian . . . and they disagree on things (or more commonly, the implications and interpretation of things) too.
Sometimes it’s shown as impossible for the time refugee in question; Poul Anderson’s classic story, The Man Who Came Early, is an example, and Harry Turtledove and Judith Tarr’s Household Gods is another; both very good, by the way.
There the time travelers are single individuals, and don’t know much about either the period they’re in, or the things they vaguely think they should be able to introduce.
At the opposite end of the spectrum, sometimes there’s a riot of modernization. Look no further than Mark Twain’s seminal A Connecticut Yankee in King Arthur’s Court for a good example, where the Yankee in question is the up-from-the-ranks manager of a Victorian-era engineering firm. Twain also has a hilarious game of baseball played in full plate armor, introduced to give the Knights of Camelot something to do once they’re obsolete, with modifications to the rules dealing with things like fastballs bouncing off breastplates and helmets.
Perhaps one of the best and most realistic (given what was known in the 1930s), not to mention funniest, is Sprague de Camp’s Lest Darkness Fall, which displaces an American archaeologist named Martin Padway to post-Roman Italy in the Ostrogothic Kingdom of the sixth century. Padway—rechristened Martinus Paduei, “of Padua,” by the locals, or “Mysterious Martinus”—has both successes and failures. He knows the period in detail, and has a good practical grasp of a number of other things . . . like how to make a still.
Incidentally, there’s an unspoken convention in a lot of science fiction that the characters in the stories don’t read or watch science fiction themselves. I’ve always considered this rather odd! Particularly considering how dominant the genre has become in our popular culture.
Hence my protagonists in To Turn the Tide, Gen-Z American Ivy League academics specializing in Classical history in a slightly alternate early 2030s, have all read the de Camp novel, though several only read it once and long before. This is by no means unrealistic; my friend Harry Turtledove has said that reading it was precisely what made him decide to study Byzantine history!
They’ve all streamed Gladiator, at one point or another, too.
History has been my hobby for a disturbingly long time; I originally considered a career in some university history department, but on investigating how that worked I went to law school, and after that decided to pick a more secure, practical, down-to-earth way of making a living . . . writing science fiction and fantasy. With a specialty in time travel and alternate history!
My research—and research is one of the pleasures of the job for me, though you have to keep it under control—has led me to the conclusion that for a time traveler to introduce innovations would be very hard, or relatively easy, depending on whether the innovation was, as my protagonist puts it, a Type A or a Type B. Type A means it can be done by the people of the time with the tools and materials they have available once they have the idea; Type B means that it’s necessary to make the tools to make the tools to build it.
And of course ease of innovation depends on whether or not the time traveler is locked up as mad, sold as a slave, or burned as a witch or not. And whether or not they just starve to death in the gutter or get a raging bowel infection and die in a pool of their own wastes. There’s a reason crossing to a new watershed with a new set of bacteria used to be very risky. Even with the pandemic, since the 1950s we’ve lost a sense of the continual menace of infectious disease. My mother grew up in Peru before the Second World War, where one of her close friends died of rabies (caught from a bat) and another person she knew of bubonic plague—the actual Black Death.
My American viewpoint characters in To Turn the Tide are professional historians, or aspire to be. When they’re unexpectedly dumped back into the early summer of 165 CE in Pannonia Superior (eastern Austria south of the Danube, roughly) they’re ready and eager to change history . . . not least because the modern world destroyed itself with thermonuclear war just as they involuntarily departed, mere instants after being informed (and not believing) that they were in the presence of a time machine.
Everyone and everything they knew and loved has gone into the stratosphere as radioactive ash. They can’t control every consequence of changing the course of events, but what could be worse than that?
They don’t know if their changes will create a new parallel timeline, or simply change the history that led to them. There’s no way for them to know or check on that. Either way, they aim to create a better course of events. And a big part of that will be introducing “discoveries” long before they were made the “first time around.”
They do have the advantage that they know something about the period. Though their knowledge turns out to be incomplete and not necessarily accurate. Little details like whether the Marcomannic Wars start that year or the next or the one after that aren’t definitely known. A difference of three years may not seem overly important from eighteen hundred years later, but when you’re the one on the ground waiting for Suebic types with homicide and arson on their minds to arrive, spears in one hand and torches in the other . . .
And they don’t know for sure what disease caused the Plague of Galen, which killed somewhere between a tenth and a third of the Roman Empire’s population in the next decade, until they see it. The ancient descriptions could be any one of a number of infections, from smallpox to measles. They could possibly do something about smallpox; there are reasons vaccination started with that disease, and in the eighteenth century. If it’s measles, everyone’s screwed, blued and tattooed.
They all know Latin, and some of them Greek . . . though it also turns out the locals can’t understand them through their thick, weird accents at first and they have to learn how to speak the local Common Latin dialect. Even then, their book-learned Classical Latin leaves them sounding like a scholar down from Oxford and stranded in Cross Plains, Texas, in 1930. Only they’re from Mars as well, in other respects.
And since the wicked Austrian physicist who sends them back by deception (and unintentionally dies in the process) was planning on landing there himself, and used pilfered R&D money on strategic purchases, they have a ton of baggage.
Quite literally: one metric ton, twenty-two hundred and six pounds and a bit.
This includes a lot of money in the form of replica Roman coin of the period, and synthetic gemstones the Romans can’t tell from the real thing. Also crates of antibiotics, and lots of books and working scale models of various simple machines. Along with potentially very important seeds of maize, potatoes and other New World crops, improved true-breeding varieties, at that. They manage to avoid having their throats immediately slit for their goods and make a friend in the Jewish merchant who discovers them right after arrival. For further details, I recommend the book!
They’ve landed in the Roman Empire at its absolute peak. At that point, Rome had one thing in common with China: it encompassed a large proportion of the human race under one government and one law, dominated by one culture.
There were probably about 200 million people or a little more alive on Earth in the year 165 CE; the Roman Empire had somewhere around 55 to 75 million of them, perhaps a third of the total, on just under two million square miles. From what’s now Scotland to what’s now Iraq, there was one ultimate source of authority—and you could travel that distance on Roman roads, and talk to anyone of note in Latin or Greek, the two dominant languages, and spend the same money and plead the same laws in the same courts.
Those people of note would read the same books, watch the same entertainments, worship different flavors of the same melange of deities, build similar mansions and temples and share the same basic view of the world. That would be more and more so as time went by, because there were powerful forces pushing toward uniformity—witness the fact that Latin replaced most local languages north and west of the Greek-speaking zone by the time of the Empire’s fall.
Which is why Romanians between Transylvania and the Black Sea today say veni for “come” and bună for “good” and unu, doi, trei for “one, two, three.” Latin equivalents, venire, bonum, and unus, duo, tres. There’s a reason they’re called “Romance” languages, and it’s not because they’re good for courtship. And “Romanian” means . . . ah . . . “Roman.”
Things peaked in the 100 to 200 CE period, and then everything . . . to sum up briefly and oversimplify just a little . . . went to hell. To give one example, Roman Britannia in the late Roman period had around twice the population that England would have on roughly the same territory in 1086 CE, when Domesday Book was compiled; it got back up to that level in 1300 . . . and then the Black Death arrived and hi-ho, a century later they were back to Domesday levels. England didn’t consistently exceed the provincia Britannia’s population until the later 1600s.
So, my time travelers are well placed. What can and cannot be done? What’s easy to do, what’s hard when it comes to technology? For the politics and personal stuff, once more . . . see the book!
My protagonist uses Type B for innovations that do require a chain of other developments in materials and manufacturing. The example of Type B he uses is Watt’s steam engine.
James Watt had the idea for his improved machine in 1763–5, while he was working as an instrument maker at the University of Glasgow. It took him a full decade of trial and error and the financial backing of the businessman Boulton’s substantial supply of money to produce the first practical engines for sale in 1775–76. This was when steam engines stopped being a proof-of-concept thing useful only for pumping out coal mines where fuel was a free good and became a source of general energy for industrial purposes.
Getting the required precision for the cylinders, the valving . . . it was an R&D nightmare even for a brilliant engineer in the center of the most advanced manufacturing technology available on the planet at that time. It was probably the earliest time someone could have made a practical steam engine using available technology. Though it required generations of theoretical work—investigations of atmospheric pressure and the power of the vacuum—before the idea became available in the first place.
In Roman times it would be even more difficult; the boring machines that Watt used for his cylinders were adapted from those used to ream out cast-iron cannon, for just one example. The Romans didn’t even have cast iron, though the Chinese at this time did, produced in the world’s first blast furnaces.
At the other end of the spectrum is the first “invention” my characters introduce, the wheelbarrow, the Platonic Ideal of a Type A. Which was invented by the Chinese as well, by the way, and not long after the time the story is set.
A wooden wheelbarrow with a few very simple metal parts was easily within the skill set of a Roman carpenter and blacksmith. And it’s surprisingly important; the alternative for short-distance transport of heavy materials like grain, bricks, sand, manure and so forth was dragging them or lifting and carrying in a basket or sack, or loading up an oxcart, which isn’t practical for really short distances or smaller loads.
For those tasks, this simple little machine gave a massive increase in labor productivity, reducing the number of workers for a given task by half or more.
Another example my characters introduce, and an even more significant one, is the cradle scythe, an American invention of the eighteenth century. It’s basically the classic hay-cutting scythe with light wooden fingers fixed above the blade and parallel to it, which allows you to cut a swath of wheat, barley, oats or other small grains and then tip them off the “fingers” in a neat row rather than scattering them.
The Romans already had scythes, since they’re a Celtic-Gaulish invention and were widely used before the Roman Empire incorporated the continental Celtic-speaking areas.
Which incidentally stretched at their peak from what’s now Ireland to what’s now central Turkey and included most of southern Germany and the Czech Republic and chunks of the Balkans. They got around!
Why is a simple little thing like a cradle scythe important?
Well, with a sickle, an average worker can harvest about one-quarter to one-third of an acre of wheat or barley a day. It’s the original “stoop labor,” too, requiring a bent-over posture even if you don’t cut close to the ground. In some places it’s even done squatting. That all means that if the harvest window is about fourteen days, one average worker can cut about three and a half to at most five acres in the whole harvest period, with weeks of sweating-hard labor.
With a cradle scythe, you can take between one and a half and three acres a day. It’s a productivity improvement of eight times or more.
And getting in the grain fast is extremely important, even leaving aside the possibility of bad weather—which farmers don’t. The grain has to be reasonably ripe to cut, but if you take too long after that, the grain “lodges,” falling over and becoming difficult or impossible to harvest. A related problem of ripe grain is “shattering,” when the heads break apart and the kernels drop out on the ground. You can stretch the harvesting period a little by staggering planting times but not by much. Essentially you have no more than four weeks and often only two or less to get the grain safely cut or the whole year’s work is lost.
This narrow “harvest window” was the main labor bottleneck of food-grain farming in the ancient world. Even with primitive tillage gear, one worker could plant five times the area of wheat or barley (or oats or rye) per day that the same worker could harvest.
So every area producing the basic breadstuffs had to carry enough harvest labor within walking distance of the fields. Or in the case of big landowners, the magnate had to import migrant gangs from somewhere else at high wages plus their keep. And wherever it lived, that labor had to eat every single day of the year, whether or not it was underemployed in the forty-eight to fifty weeks that weren’t spent harvesting the grain.
That had all sorts of knock-on effects, and was one of the basic reasons why the level of urbanization was limited—in the whole Roman Empire at its Antonine peak most likely a bit more than twelve percent. In Italy it was an astonishing (for a preindustrial economy) twenty-five to thirty percent, but the huge megacity of Rome depended on wheat, wine, wool and olive oil brought and bought (and taxed) from all over the Mediterranean basin.
So there’s nothing complex about making a cradle scythe. Any competent carpenter could do it in about two hours with the materials to hand, starting with a scythe. But it changes the whole economic structure of agriculture, which was the major occupation until quite recently. Suddenly you don’t need to carry eighty or ninety percent of that extra harvest labor year-round, or pay premium wages for temporary hires; it’s not necessarily there on the farm or some nearby village or town or remote hill-country district eating some of the last harvest every day of the year.
You can sell that food instead. Other people can buy it and do other things.
Horse-drawn reapers like Hussey’s or McCormick’s are even better, but that would be much more difficult—there are Type B elements.
Another example of a simple concept with serious knock-on consequences is the wood-framed saddle with stirrups; possibly another Chinese invention, or taken up by them from the Asian horse nomads to their north. The Huns didn’t have stirrups when they fought the Romans in Gaul in 451 CE, but the Avars did, when they arrived in Europe from the Asian steppes about a century later.
You can have workable cavalry, horse archers or even heavy cavalry in complete armor, without stirrups—but they don’t work nearly as well as they do with stirrups, and the necessary skills are harder to learn and maintain. Without stirrups, a cavalryman’s weapons have to be used with the strength of the upper body alone, because his legs are holding onto the horse. This is, incidentally, probably why cavalry in the ancient world used an arm-powered stabbing motion with their spears.
With stirrups, you can brace your feet and use a bow or a sword almost as if you’re standing on the ground, adding the muscle power of your core and legs. With stirrups and a raised cantle at the rear of the saddle you can also use a “couched” lance held underarm, with most of the weapon ahead of you and the momentum of the horse providing the punch behind the point. This was a very important tactical innovation that didn’t happen until nearly a thousand years after Marcus Aurelius. If you take a look at the Bayeux Tapestry scenes of the Battle of Hastings in 1066, the Norman knights are still mostly shown using an overarm stabbing motion. Stirrups also make it much easier to guide the horse with your legs and knees alone, which made mounted archery at speed very much more efficient.
Try riding bareback at a trot and you’ll see what I mean. It’s possible but not easy, because you’re using an inward clench of your thighs rather than your legs and knees to cushion the up-and-down motion. Try pulling someone out of the saddle if you’re bareback and they’ve got their feet in stirrups. You’re using your arms against their legs. Because your legs are otherwise occupied.
There’s absolutely nothing in the saddles of the nineteenth century that couldn’t be made in the Rome of the Principate. For that matter, with a few minor substitutions of wood and leather for iron parts, they could have been made by the Yamnaya, the Proto-Indo-Europeans who (probably) domesticated the horse, back in the fifth millennium BCE.
They just didn’t have the idea. Nobody did, not for four thousand years and more of riding.
It turns out that there are a whole raft of innovations like this. The foot-treadle-powered spinning wheel, also handmade by individual craftsfolk, increases productivity by ten times over the handheld distaff-and-drop-spindle used in antiquity. A treadle loom with a flying shuttle, the final handworked version replaced by power looms during the 1820s and ’30s, has an even greater advantage over the looms used then. For that matter, the Romans didn’t have the hand crank—that thing you see in old pictures of people winding up a bucket from a well. They used spokes sticking out of an axle to turn it, and a rather clumsy camming system to turn rotary motion into linear from a watermill. They did have watermills, but hadn’t thought of windmills . . .
And then there’s gunpowder. The Romans had saltpeter, charcoal and sulfur, the first and last as medicines, fumigants and bleaching agents. They just didn’t know what happens if you grind them up, mix them together wet in a ratio of 75-15-10, dry and grind and sieve the resulting cake . . . very, very carefully . . . and apply a light. It was, once again, the Chinese who worked that out.
This raises the question of the consequences of the innovations the time travelers introduce. Those don’t follow in a one-to-one or obvious way, nor are they going to be necessarily the same as they were in the history where they were discovered.
Note that the Chinese were extremely inventive throughout their history. Up until the early modern period it was the Chinese who made most of the advances, or at least did them first—the ones mentioned, plus rockets, crossbows, paper, printing, sternpost rudders, long-distance canals . . . the list goes on and on.
Yet it wasn’t the Chinese who had the first Industrial Revolution. It wasn’t Chinese steam gunboats that sailed up the Thames and the Seine to thrash the natives, peddle cheap dope at gunpoint and burn down Westminster or Versailles to make a point and get souvenirs for the folks at home.
Like Queen Victoria’s Pekingese pup, brought back from the sack of the Summer Palace outside Beijing in 1860. Which she named “Lootie,” in a charming display of Victorian candor.
Why not? Why did Europeans end up kicking China around the block for generations, rather than vice versa?
This is the subject of a lot of historical controversy, to put it mildly. There are all sorts of political, cultural and religious factors involved.
One important reason among the others is that the Chinese innovations were introduced gradually. China had coal-fired blast furnaces on a large scale in the eleventh century, seven centuries before the same invention was (independently) made at Coalbrookdale in England and while those Norman knights I mentioned were stabbing overhand. They very nearly invented the “cotton jenny” in the fourteenth century. By that time they were drilling wells for brine thousands of feet deep and using natural gas to evaporate the water and produce salt. There were reasons they thought of themselves as the Middle Kingdom, the home of civilization, and everyone else as a deplorable fringe of barbarian savages . . . in addition to the standard human instinctual “my tribe good, your tribe stinks” reflex, that is.
Since China introduced these inventions gradually, the growth of population had time to absorb all the increase in productivity. Some historians have called it a “high-level equilibrium trap,” and it’s very Malthusian. You eventually get a bigger population, but one just as dirt poor on average.
In Europe, and specifically Britain, the inventions that led up to the Industrial Revolution proper were introduced in a long burst covering no more than a few centuries. They produced a huge surplus, which increased per-capita incomes (already higher than most of the world) to unprecedented levels, which provided a mass market for ordinary consumer goods, which in turn encouraged more inventions in a virtuous feedback cycle that enabled Western civilization to dominate the planet and escape the Malthusian trap. This is, to put it mildly, a gross oversimplification, but I think it’s true as far as it goes.
When Western Civ wasn’t expending its surpluses in ever-more destructive wars between its component parts, of course. The preparation for those wars also drove the process of innovation . . .
See Chapter 1 of To Turn the Tide!
The results when a suite of inventions are introduced from the outside can be more dramatic still; witness the astonishing rise of Meiji Japan. And they can be even more unpredictable than most of history, which is highly contingent anyway. It’s my belief that if you could “rewind” history to any given point and then let it run forward again, even without time-traveler meddling, the results would be startlingly different most of the time. Next time Franz Ferdinand’s driver won’t take a wrong turn!
The Roman Empire spread a number of economic institutions and technologies. Together with the “Roman peace,” which obviously did not end wars but did reduce them substantially, and the creation of a huge free-trade area with common currency and legal forms, this allowed an unprecedented degree of specialization and division of labor. This in turn resulted in a level of population, long-distance trade, monetization, literacy and urbanization that wasn’t surpassed again after the fall of the Empire until the modern period.
For example, the Roman army’s minimum height requirement was several inches taller than that of the army of Napoleon. The city of Rome had at least a million inhabitants in 150 CE, and that was the largest urban population in the world in one spot. No European city matched that again until London in the year 1800, though some Chinese ones did for a while, and Edo/Tokyo in the late eighteenth century.
That’s the condensed version, by the way.
But the Empire is at its peak between 100 CE and 200 CE . . . and 165 CE is when my time travelers arrive, just when it’s about to run into the wall and go splat.
Though not as quickly or decisively as you can manage with thermonuclear war. Isn’t progress grand?
Effectively the time travelers dump, over the next forty years, 1,600 years of technical progress into the stew; first the highly significant Type A ones, and then more slowly and with difficulty some of the even more important Type Bs. Not to mention that they know the precise location of mineral deposits . . . including things like gold and silver.
Plus extra items of mental, ideational technology, like positional arithmetic, modern algebra, double-entry bookkeeping, joint-stock corporations, heliocentric astronomy, the germ theory of disease and antisepsis.
Many of those are Type A, too. Most of the drop in death rates in the First World between say 1853 and 1953 (the latter being my own incredibly ancient date of birth) wasn’t due to antibiotics, which didn’t come into play until the 1930s and weren’t common until later. It was due to fairly basic sanitation measures informed by germ theory.
Though the time travelers get Galen, the famous court physician of Marcus Aurelius, to take credit for the medical stuff! If there was one thing Galen was good at, it was academic bun-fighting, and that is not a modern invention.
And since the Empire is united and has good communications . . . and (slight spoiler) they get the Imperial government mostly on their side in the first few years . . . the innovations spread very, very rapidly. Helped along by things like paper and printing!
The consequences? Well, I think the way I worked them out is interesting. To find out, you need to read To Turn the Tide and its sequels!