Giving Radio to the Romans

"Cross the river and go to Rome! Alea Iacta Est!" Hey, wait a minute. Something here does not seem right... ^note A-ha! That stenciling is using Arabic numbers, not Roman numerals!

Marina: You're not worried about changing the past and messing up the future?
Pearl: Nah. I'd only make good changes. Like giving cellphones to cavesquids.

— Splatoon 2

The problem with the past is that it's so uncivilized, but any time traveler worth their salt can fix that. Just introduce it to the delights of modern technology, several centuries early. You may need to go through a few intermediate stages, replicating the history of technology on fast forward, but you know exactly what needs doing. How difficult can it be?

There are two types of time travelers who try this stunt — the unwilling ones, Trapped in the Past with just the right skills needed to jump start the industrial revolution, and the reckless ones who don't care about paradoxes, they just want to rewrite history for the better.

Either way, this is a long term plan. Even optimistic heroes will expect to take a few years to get the desired results. Realistic ones will consider it a lifetime's work. The hero can't leap straight to modern technology; they have to get the past society to go through all the intermediate steps first, or they won't have the necessary tools to make the tools to do the job. As such, this is typically the plot of an entire book, or even a series.

Ancient Astronauts and explorers rediscovering lost colonies occasionally fall into the trope, if the story goes into detail about how they introduce technological advances, but they normally gloss that over. By contrast, works in this subgenre typically go into great details about the new technologies being introduced to the past, and their social impact, as well as addressing all the problems that would realistically crop up.

If the stranded party has a phone to a high-tech society, whether in the future or on another world, this trope can still apply. The phone can provide them with all the information they need, but they still have to deal with the immense practical problems involved in getting from medieval to modern technology. It would still take decades to get 14th century England from church bells to digital clocks, even with an internet connection to the present day, and the full resources of the kingdom at your disposal. However, if the stranded party can get actual physical objects from their high-tech friends, the difficulties melt away, and this trope does not apply.

If a Hero succeeds, there's still a risk of going horribly wrong, going horribly right, or both.

If the Hero went back in time with the purpose of using this trope to change history (such as preventing the Fall of Constantinople by going back to 1453 and giving the city's defenders modern weaponry and teaching them modern tactics), then it also counts as trying to Set Right What Once Went Wrong (or Make Wrong What Once Went Right, depending on the perspective).

Fridge Logic would dictate that this would result in an infinite technological loop: Suppose the radio was invented back in 50 B.C. by a time traveler. Since this means that time travel is possible, eventually somebody from the future of the timeline created by the original time traveler would travel back to an even earlier time (for example, 800 B.C.) and give radio to the Akkadians or something. Then a time traveler from that timeline would introduce radio even father back, repeating until advanced technology is being given to the earliest species able to use it.

Compare with:

• A Little Something We Call "Rock and Roll": When this is done with pop culture instead of technology.
• Technology Uplift: Basically this trope, but without the time travel.
  • E.T. Gave Us Wi-Fi: A kind of Historical In-Joke that suggests that a type of real-world technology is actually of alien origin or design.
• Low Culture, High Tech: Will result if the time traveler doesn't lay the groundwork for the low tech people to properly replicate the future tech.
• Timeline-Altering MacGuffin

Contrast with:

• This Is My Boomstick: The Hero only wants to impress the locals short-term.
• Cargo Cult: The primitive culture gets technology but concludes that the artifact is a god.

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Examples:

Anime & Manga

• The Vision of Escaflowne: Basically the background of the Zaibach Empire. Emperor Dornkirk (who was in this reality Isaac Newton) brought the gift of science, culture and technology to the weak, incompetent farmer-nomads of the Zaibach area in Planet Gaea, developing themselves into a force able to defend themselves, eventually building their own industrial civilization and turning into a warmongering empire.
• Magic Artisan Dahlia Wilts No More starts with modern day salary-worker Dahlia dying from overwork and being reincarnated as the daughter of a magitek-craftsman in a fantasy world rife with magic and monsters. With her memories of life on Earth and training from her father, Dahlia grows up to introduce magically-powered counterparts of common household appliances (like hair dryers, portable cooktops, and water heaters powered by magic crystals) and materials (like fabrics waterproofed with slime essences) to the high-fantasy world of Ordine.
• Maoyu: The Demon Queen, a peace-seeking sort despite her name, consorts (literally) with the opposing Hero to bring modernizations to farming, industry and navigation that help humanity avoid the need for war. Pitfalls are expected by the leader as not everyone on either side of the war is willing to cede control over those who once lacked control of their destinies or did things that others expected because of their heritages. And then because somebody else is also able to provide advanced technology and uses it to arm her enemies with muskets, the Demon Queen is forced to introduce rifles to surpass this.
• The Master of Ragnarok & Blesser of Einherjar: This is a major part of the plot. Yuuto has his smart phone (which can be charged via solar energy, fortunately) and is able to communicate back to Earth. A big part of the wolf clan's rise in power is him rapidly introducing new technologies and military tactics.
• Zipang sends a modern Japanese naval ship to World War II. A good chunk of the plot is about whether or not to give the metaphorical radio to the metaphorical Romans.
• Thermae Romae doesn't have a person that gives technology to Lucius as he just randomly timetravels to modern Japan, but other than that, this story fits this trope as Lucius sees Japanese bathing culture and designs his own baths for the people.
• Restaurant to Another World had a younger Tenshu sell a bag of Potatoes to Emperor Wilhelm from the fantasy world that the Western Cat Restaurant connects with every Saturday, just so the Emperor could make his favorite dish whenever he wanted. In doing so, the "Cobblers' Tubers" wound up ending a great famine that the Emperors' nation was facing, however Tenshu doesn't even realize this.

Audio Plays

• Big Finish Doctor Who: The adventure "Colditz" has the Doctor and Ace's capture at Colditz Castle turn out to be much more complicated when a Nazi scientist shows up from an alternate timeline where her side was victorious. While the Doctor thinks it's because the Nazis got their hands on the TARDIS, it's actually because they got their hands on Ace's CD player - and the laser technology inside.

Comic Books

• Disney Mouse and Duck Comics: Defied, as the government from the future doesn't like to have their history altered and will stomp on any attempt to do so through the Time Police. Especially notable in Paperinik New Adventures, where the Time Police' intervenes fully knowing that stopping the Raider from helping some scientists developing nuclear fusion will result in Duckburg's destruction.
• El Eternauta (second part): The protagonist decides to give to a tribal After the End civilization of the future, enslaved by an alien race, knowledge of modern weaponry and machinery. Since the available tools and labour skills are quite crude, they can't go beyond mid-XIX century tech: simple pistols, muskets and cannons and basic steam engines (making it a Steampunk comic in 1976).
• Marvel 1602 has a time-displaced Captain America sent back to Elizabethan times. When asked to return to the future, he insists on staying to try and build a better America from the beginning — which he does in small ways, such as helping a group of colonists survive a winter that should have wiped them out, or warning the natives against selling their land to unscrupulous capitalists. The final touch comes when, because of his actions, the American colonies declare independence from Britain 174 years early. It also has consequences beyond his control — his presence causes the Marvel Universe to impose itself on the past, and period versions of the X-Men, Avengers and other superheroes start appearing.
• Pax Romana: The ailing Catholic Church sends a paramilitary group back to 312 AD to use both advanced technology and knowledge of future events to help the Roman Empire set up a stronger foundation for the Church. Things don't go as planned, but, even so, technology and culture advance much quicker than in the unaltered timeline, eventually giving rise to an utopian society with numerous off-world colonies by 15th century.
• Supreme Power plays with and subverts this. When a new commander of the "Hyperion Project" comes on board, he can't believe the scientists have been wasting decades concentrating on alien DNA rather than the highly advanced spaceship it came from.
  General: You had access to an artifact from a non-human civilization! Do you realize what you had, and what you let get away from you? Do you? Then let me explain it to you! Imagine handing an F-16 to the Aztecs in 1521, when Cortez was at war with them, and instead of learning to fly so they could slice Cortez and his army to shreds, they cut off the wings to use as shields, the guns as clubs, and they take off the wheels because they figured they would look really cool hanging from the temple ceiling!
• Tim Traveller: In one story, Tim is annoyed that his dad doesn't get modern technology, so decides to remedy it and goes back in time to show his laptop to some cavemen. They don't understand it and just try bashing it, which leads them to invent fire.
• What If? v1 #33 features Tony (Iron Man) Stark becoming trapped in the time of King Arthur. He starts advancing the technology level single-handedly until he can recreate his Iron Man armor.

• In the backstory to the version of Flash Gordon in Dynamite Entertainment's Massive Multiplayer Crossover Legenderry: A Steampunk Adventure, he found himself on the world of Legenderry hundreds of years before the story begins. He puts himself in suspended animation and periodically awakens to give the settlement around where he landed a nudge, so by the time of the story, the city of Landing has the highest tech in the world; still steampunk, but advanced steampunk.
• In a crossover story between the Justice League of America, the Justice Society of America and the All-Star Squadron, time-travelling villain Per Degaton attempts to acquire weapons and technology from the future to conquer the world of the 1940s, but discovers he can travel between alternate Earths after accidentally traveling to Earth Prime and then to the Limbo between universes, where he gets the Crime Syndicate of America (formerly of Earth-Three), to steal nuclear missiles from Earth-Prime's Cuban Missile Crisis in 1962, which he brings to Earth-Two's 1942.

Fan Works

• Cycle has an accidental version of this when Marc and Echo get their hands on a bag of Robin's possessions, including a modern MP3 player. When Robin finds out, she is astonished and impressed that two medieval-era pre-teens were able to figure out how to work her "magic music box" through pure trial and error without any concept of advanced technology or even the capacity to read the words on the screen.
• Lulu's Bizarre Rebellion: In a rather more short term version of this, the Chinese Federation uses an as-yet-unknown method to bring season 2 knightmares during their season 1 invasion of area eleven, culminating in them deploying the Guren S.E.I.T.E.N, piloted by the zombified Naoto Kozuki, Kallen's brother.
• My Choices: Twisted Tales Through Time: Blue Star — Twilight, after being stuck 1000 years in the past and taking on an alias — brought numerous technological advances to Equestria from the future and did a lot of further building on them within the past, beyond what had been accomplished in her native time, in addition to introducing modern political and cultural concepts ahead of schedule. Ironically, one of the eventual results of this is a stable time-viewing spell, which would have allowed her to avoid the whole situation if it had been around in the original timeline.
• The Necromancer: After Sauron escapes death by arriving in Storeybrooke to retrieve the One Ring, he returns to his original era with a large collection of modern guns, which the residents of Storeybrooke know are too dangerous to be left with his forces.
• Purple Days: By the time of the Final Loop, Joff gathers a group of Maesters, merchants and thinkers and begins doling out examples of the technology he's witnessed across his many lives and opening the Crown's purse for investment, hoping to accelerate Westeros' level of technology and innovation as much as he can before the Long Night arrives for the last time.
• Saruman of Many Devices: The basic premise is this — the title character aided by an AI that, if not inherently benevolent, is still opposed to Sauron on the grounds that he introduces stasis, while the AI's directive is to bootstrap human civilisation. Consequently, it introduces initially renaissance-era technology, including fairly advanced steelworking and of course guns to Middle Earth, before moving on to closer to the Napoleonic era, then later Victorian era (the Martini-Henry rifle, mainstay of the late 19th century British army, is given as one example), in an attempt to bring forth an industrial era. Specifically, to the Uruk-hai working for him already, then the rest of Middle Earth.
• A Song of Ice and Fires That Weren't All My fault has Harry Dresden and his daughter displaced to Braavos about a decade or so before the events of A Game of Thrones, just after Robert's rebellion. After a couple of years of keeping his head down for his daughter's sake, Harry decides to engage in a basic effort to advance technology, with the vague aim of, somewhere in his centuries long lifetime, reaching the point where he's able to hex it again. His being a big fan of Muggle Power (despite being a powerful wizard), and having a pronounced dislike for feudal lordship, are also factors. One of the main initial successes is starting up a printing press.
  
  The fic also touches on some of the problems with an individual doing this. While Dresden has a better understanding of fundamental science than most, his knowledge is still fairly vague and his initial almanac (containing stuff like basic germ theory and physics) is likewise relatively limited (though this problem is ameliorated by the arrival of Lydia, his spiritual daughter, created by Lash's sacrifice, a spirit of intellect who knows everything that both Dresden and Lasciel did). Additionally, his magical compasses, which function as a sort of magical GPS (with two compasses, a chart, and a little geometry, you can figure out pretty much exactly where you are anywhere in the world), are a runaway success, but also hit the small snag that only he can make them. And finally, he's extremely reluctant to introduce gunpowder, on the grounds that it'll make the conflicts even bloodier. However, he ultimately does so after dragons start appearing beyond his control, to give ordinary humanity a fighting chance.

• The (Questionable) Burdens of Leadership of a Troll Emperor begins with Naruto and Xanna traveling to the Stargate-verse sometime around the 15th century, taking over a minor Goa'uld's world, and improving its technology over time as they build an empire that eventually spans multiple galaxies. While they do things "slowly" to keep the population from being completely reliant on them, said world goes from Stone Age level technology to at least a century or two ahead of Earth in less than six hundred years. It certainly helps that once the empire has advanced far enough for it to be useful, Xanna and Naruto call in the favor the Asgard owe them and has them teach their people.
• Star Wars Episode I: The Familiar of Zero features an interesting example in that all of the technology presented is used to improve quality of life and standard of living, such as running water and indoor plumbing. Both massively reduce disease within the cities.

• A major plot point in May The Future Be Bright: Kiran's Story, Kiran's desire is to transform not only the Zenith continent into a more advanced civilization, but also all the timelines and continents all the heroes he has summoned came from. Apparently this is because he considers the people from the universe of Fire Emblem worthy to possess the technology to save themselves from extinction unlike the people of his original world. He explains to the heroes that no matter how much they fight for the future of humanity, it's gonna be for nothing if they don't make the science progress until the point it would allow sailing efficiently through the stars because even if every evil dragon that threatens humanity fails at exterminating the life on earth, the sun is gonna transform the planet into a hell in a very distant future and there's nothing that can be done to avoid that fate. He also seems to be an Immortality Seeker in order to see the end of his mission.
• A minor plot point in Relic Of The Future is Jaune's casual decision to pawn off his scroll in Vacuo to pay his travel expenses. It's not until many chapters later that he realizes his time-travel landed him about a decade before he first attended Beacon, making the scroll far more advanced than anything on the market at the time. The merchant he sold it to reverse-engineers it and becomes the CEO of one of the biggest tech companies in Remnant — and he makes sure Jaune gets his share of the wealth, even if he doesn't notice until years later.
• Period Piece is about Katarina Claes bringing the sanitary pad to her Medieval European Fantasy world. Since she was only a consumer in her previous life, it does take some trial and error to find the right materials and a way to mount them.
• Dedicated Hearts made Fullmetal has the Elric brothers sent to the Attack on Titan world by the Truth. Once there, they quickly spark a revolution with their knowledge in Alchemy, automail and general science for Paradis Island, to the point that by the time the Return to Shiganshina arc rolls around, the military has developed artillery cannons powerful enough to blast the Titans to bits without risking themselves, and several soldiers who lost their limbs in battle are getting automail prostheses. Moreover, they're also starting the development on electric generators powered by gas or waterwheels. When it comes down to a fight against the nation of Marley; whose military superiority has been dependent entirely on their control over Titan Shifters, the Eldians of Paradis are now on a more evened playing field both technologically and scientifically. Following the four-year timeskip, Paradis had advanced to now include both a fifth branch of the military made up of Alchemists, along with their society now using steam locomotives and automobiles to travel around the island that at times the Elrics feel as though they were back home in Amestris.
• In Thy Good Neighbor, Lord Paramount Rickard Stark is given a copy of a very advanced tome detailing farming techniques and technology. It's deconstructed in that the North does not have the necessary seeds, proper terrain or metalworking expertise in fully developing the ideas, even if Rickard were inclined to invest in it, and the nitrogen compounds the book recommends for the formulation of fertilizer remind him far too much of the Tragedy of Summerhall for comfort.

Films — Live-Action

• Crusade in Jeans had The Hero do this too, by using the assembly line principle along with an Ipod to bribe the baker to bake a lot of bread overnight.
• The Philadelphia Experiment II combines this with Set Right What Once Went Wrong: A stealth aircraft armed with nuclear bombs is accidentally transported back in time to Germany in 1943, where it's captured by the Nazis and used to bomb several cities in the eastern United States (including Washington, D.C.), with the end result that the Axis Powers won World War II. Needless to say, the protagonist from the original movie is the one who winds up having to fix this mess.
  • This is combined with Low Culture, High Tech when the aircraft is destroyed on its final run. The Nazis, of course, want another and the scientist who claimed to have invented it can't replicate one. In the revised history, his son trying to clear the family name.
• Sengoku Jieitai 1549 (also known as Samurai Commando: Mission 1549) features failed experiment which leads to time travel of a wounded samurai to our times and a group of soldiers to the year 1549. When the second group of soldiers goes to 1549 in a search and rescue mission they discover, among other things, a refinery.
• Minor example in Night at the Museum. Larry accidentally left behind his smartphone back in post-WWII United States (specifically, VJ Day), and a passing seaman picks it up, takes it home, and takes it apart. The seaman's name? Joey Motorola.
• Played for Laughs in Hot Tub Time Machine - Lou decides to stay in the 1980s instead of returning to his present, and spends the intervening time becoming a billionaire by getting in on the ground floor of every important innovation between then and now (and naming them after himself).
• Star Trek
  • In Star Trek IV: The Voyage Home, Scotty introduces the formula for transparent aluminum in 1986 which is presumably early in their timeline. Though Dr. McCoy kind of lampshades this, Scotty counters with the notion that the guy he's showing it to was possibly the original inventor. Dr. McCoy also gives an elderly 1986 hospital patient 23rd century medicine that rapidly remedies her dialysis.
  • Happens inadvertently in Star Trek (2009) when Nero and the crew of the Narada accidentally Time Travel from 2387 to the year 2233 and immediately attack the USS Kelvin. Data collected of the 24th century Narada during the attack was reversed engineered handwaving why the 23rd century of the Kelvin Timeline is cosmetically advanced compared to that of the original timeline.
• This happens in several ways in the Terminator franchise:
  • The Terminator was originally going to end with two technicians investigating the destroyed Terminator. It would then be revealed that they worked for Cyberdyne, the company that originally made it in the future.
  • Terminator 2: Judgment Day shows that this happened, the terminator killed at the end of the first movie provided the technological base to make SkyNet, creating an almost Stable Time Loop.
  • It explicitly happens in Terminator 3: Rise of the Machines, where the T-X uses nanomachines to take control of electronic devices and primitive robots.
  • And once again in Terminator Genisys, where the T3000/John Connor is sent in 2014 to share his knowledge with Cyberdyne to create SkyNet in the form of the Genisys artificial intelligence software.
• An accidental version occurs in the Kamen Rider 40th anniversary movie OOO, Den-O, All Riders: Let's Go Kamen Riders, where Eiji Hino and Ankh end up tagging along on one of the DenLiner's trips to the past. Ankh loses one of his Cell Medals, which Shocker finds and reverse-engineers in order to produce a monster powerful enough to defeat the original Kamen Riders, allowing them to Take Over the World.
• A variant happens in Avengers: Endgame. Seemingly no one in the universe has discovered the Pym Particles other than Hank Pym. But then a time-travelling Nebula is captured by Thanos in the past, and her vial of Pym Particles is reverse-engineered and replicated to the point Thanos's whole army can be taken to the future.

Literature

One person

• In Accomplishments of the Duke's Daughter, Iris laments that she doesn't have the knowledge required to start a technological revolution, but her Past-Life Memories of being an accountant allows her to create an economic revolution by introducing modern financial, educational, accounting and administrative policies (though the concept of a "sales tax" proves to be a non-starter).
• A Connecticut Yankee in King Arthur's Court is one of the first works to use this trope or to seriously examine the difficulties behind it. The aforementioned Connecticut Yankee attempts to introduce both modern technology and modern egalitarian ideals into a medieval feudal Camelot, but events spiral out of his control and cause the timeline to snap back into course.
• Ladies Whose Bright Eyes, written in 1911 had a mining engineer do the same, but finds he can change little.
• Poul Anderson showed the problems with this in his short story The Man Who Came Early, in which an American soldier stationed in Iceland is sent back to the Viking Era after being hit by lightning. Luckily for him the Icelandic language has not changed much since then. But all his attempts to change history fall flat on their face, predominately because while he has some ideas to implement, he lacks any sort of practical skills to do so as he was just a Military Police grunt, and, far more importantly, lacks common sense of what are his realistic capabilities. When he tries to show the Vikings how to make compasses, he has no idea where to find or mine magnetic ores. When he tries to show them how to build more modern sailing vessels, the Vikings point out that such vessels are too cumbersome to dock anywhere where there is not a ready built harbor, an obvious rarity in that time period, and so on. The story's main point is that introducing future inventions, while possible, is immensely difficult, because most advances are useless without an equally advanced society or infrastructure (and often both) to support them or outright impossible to make without them. In the end, his last technological artifact, a pistol, runs out of ammo during a fight to the death, and he has far more results using his martial arts training to dispatch the men sent after him in a blood feud. He is eventually killed, and at most, he influences a noble family to Christianize faster, as the family that took him in listened to him talking about Iceland becoming Christian in the future.
• In Ascendance of a Bookworm, the Reincarnate in Another World main character, Myne, slowly rises up from a poor commoner as she begins selling knowledge/products from her original world. Thing is, this isn't even what she's trying to do: inventing paper, mass producing ink and making shampoo are only so that she can make books more accessible and not feel so totally disgusting while living in poverty, the other stuff came when she needed the money to get access to Magic Tools and stave off the Devouring.
• In the Known Space novel Destroyer of Worlds, a lone Pak (a highly intelligent, super strong, long-lived creature) gets stranded on a primitive world. He introduces the natives (who have Bronze Age technology) to technology in steps, hibernating for unknown periods between each step. He needs to do this to escape the primitive world, by reaching the ramscoop level.
• In Conrad Stargard by Leo Frankowski, Polish hiker Conrad Schwartz, in a drunken stupor, bypasses all kinds of security and stumbles into a historical-research time portal (created, coincidentally, by his cousin) and awakens in thirteenth-century Poland, where he has just ten years to industrialize and unite his nation before the Mongol hordes arrive.
• Inverted in The Centurions Empire by Sean Mc Mullen, the premise of which is that Ancient Rome developed a medicine that allowed the human body to survive being frozen, and promptly started storing its best and brightest. After the empire collapsed the one survivor set up shop in an English village, being unfrozen when they needed his military expertise.
• A Hero's War sees an engineering student pulled into a world with essentially medieval technology plus Functional Magic — and threatened by hordes of monsters. He sets out to kick-start the industrial revolution, bringing insights from Earth about steelworking and medicine and standardisation and even powered flight, in hopes of building up a military and logistical force capable of winning the war — although building the tools necessary to build the tools capable of making even a ballpoint pen is a tremendous undertaking.
• In Terry Pratchett's short story Once and Future a time traveler called Mervin finds himself not only trapped in the past, but in a past that never existed; the Anachronism Stew that was King Arthur's time. Working as a doctor for a village in Sir Ector's demenses, he quickly realises that what they need is a great and noble leader, gimmicks up an electromagnet to hold a sword in a stone, and waits for a candidate whose body language suggests he's sensible enough to take advice. It works, although not quite how he expected.
• Lest Darkness Fall: Martin Padway is struck by lightning and finds himself in sixth-century Rome, on the verge of its ruin at Justinian's hands and the onset of the Dark Ages. He may be able to save civilization, if he can only get the ruling Goths to grasp the value of his innovations. Notable as it does take a few tries to figure out what does and does not work... Also notable in that one of the first and most important inventions he introduces is brandy. In itself, useless. For making money and building a place in society, invaluable.
• Brought later full circle with To Bring The Light by David Drake, which is bound with Lest Darkness Fall in some editions. In this story a woman from Justinian Era Rome gets sent back to the founding of Rome and must use the inventions of later Rome to help found it...
• As a Take That! to Lest Darkness Fall, Frederik Pohl wrote the short short story "The Deadly Mission of Phineas Snodgrass." Snodgrass gives the Romans modern medicine and agriculture…but not birth control. Oops. The exceedingly overpopulated alternate timeline he created decides to do something about it. For added fun, it explicitly mentions the de Camp story. Although clearly the author didn't know that real life Romans had a common method of population control (or maybe he did, but felt it would shock the readers). After the baby was born, if it was unwanted, they would leave it out to die in the woods or street. This was called exposure, and it was common enough to play a major role in Greco-Roman mythology and folk tales.
• Temporally inverted in Philip Francis Nowlan's Armageddon 2419 A.D., or as it's better known, Buck Rogers in the 25th Century. Rogers, in the various versions of his tale, brings lost knowledge and a certain 20th-century vitality to future America and/or Earth as a whole.
• Lord Kalvan Of Otherwhen by H. Beam Piper. Pennsylvania cop Calvin Morrison runs afoul of the Paratime Police and is accidentally transported to a medieval alternate Earth where a corrupt theocracy controls the secret of gunpowder. Pretty realistically handled — he knows the basic formula, but also knows that there were steps in making it consistent that he needs to rediscover, and he has to convince wary leaders to build up the entire infrastructure for gun manufacturing from scratch.
• In one of Harry Harrison's The Stainless Steel Rat novels, the main character ends up in a pocket universe that contains an alternate version of the Napoleonic Wars, in which the Big Bad gives Napoleon 20th century artillery. Napoleon, already an artillery genius, uses the technology to easily beat all of Europe into submission. The main character has to explain to an English nobleman the mechanics of one such cannon, who then uses it to sink a ship with a few shots.
• The Other Time (started by Mack Reynolds, completed by Dean Ing after Reynolds' death) features a modern day (1980's) anthropologist doing field work in Mexico who gets thrown back in history to just the right time to run into Cortez and the conquistadors. The language issue is avoided as the hero (being an anthropologist) naturally speaks Nahuatl and Spanish.
• Harry Turtledove, The Guns of the South: Time travelers from the near future supply modern guns to the Confederates during the US civil war.
  • The computer engineer among the "Rivington men" of The Guns Of The South, who says that if and when the computers they brought back to Confederate America break down, he won't be able to fix them, because the time period doesn't have "the tools to make the tools to fix them, and probably a few iterations after that." Reproducing AK-47s though, is within their grasp (see Afghani copies of the AK-47 made in the 1980s).
  • Also something of a deconstruction, with the Rivington men outright telling the Confederates (at least prominent ones like Robert E. Lee and Jefferson Davis) that they're time-travelers, and then the Southerners successfully defeating them despite their technological superiority when they turn against them.
• Belisarius Series: Two factions from the far future, one attempting to make a future hostile to transhumans and the other trying to save a tolerant future, attempt to change the past by introducing gunpowder and the knowledge of its use to certain factions of late antiquity, sparking an arms race in which the Eastern Roman Empire (and allies) and the Malwa empire of India blitz past several centuries’ worth of advances in firearms, rocketry, and explosives technology in a handful of years. Towards the end of the war, the Romans do, in fact, get radio. Neither the future that was nor the future if The Bad Guys Win happen, as a new Golden Ending happens that is significantly different than ours.
• He Who Fights With Monsters: For the most part not an issue, because Jason was never a scientist and so can't really explain the way his world's technology works. Plus, the world has enough Magi Tech that they don't really need a technological uplift. However, when he tries to explain to Clive how tides and gravity work, the Goddess of Knowledge immediately tells him to stop; even though Jason doesn't understand the concept perfectly, he understands enough for Clive to figure out the rest, which would be an unfair advancement for the world.
• The Hitchhiker's Guide to the Galaxy
  • In The Restaurant at the End of the Universe, Arthur Dent attempts to prompt the evolution of the human race by teaching the primitive humans how to play Scrabble.
• John Barnes's Timeline Wars trilogy: Patton's Spaceship, Washington's Dirigible, and 'Caesar's Bicycle all see this trope used, as part of a multi-universal time war against Carthagian descended timelines. The first book centers around a downplayed example, with the primary antagonists giving the Nazis technology from the end of World War 2 in the 30s (specifically Me 262 fighter jet aircraft and Panther tanks, both with their flaws fixed), which meant that it was relatively easy to adapt to produce the new weapons while still providing an overwhelming advantage against the Allies. The main character gives a little assistance to the Allied Resistance, but since he's not an engineer or physicist he can't help too much. Mostly he just gives some hints and they figure out how to build nuclear weapons and space ships on their own. And also laser cannons, to the main character's shock.
• Isaac Asimov's short story The Red Queen's Race is about a man who attempts to do this to ancient Greece, sending back modern knowledge with the intention of getting the scientific revolution going in classical times and giving the world a two-millennium head start. However, the professor who did the translation into ancient Greek realizes what was up, and so deliberately included only such information as would explain certain before-their-time theories that really did appear in ancient times, thereby creating a Stable Time Loop.
• A variation from K.A. Applegate's Everworld series: the heroes, while trapped in a Fantasy Kitchen Sink alternate world, introduce telegraphs to an Elven city, and use the technology to get rich.
• Conversed in Kir Bulychev's short story "Паровоз для царя" (lit. Steam locomotive for the tzar), where the characters discuss how hard would it be to pull this off in Real Life: if you were to give the tzar the technology of automobiles, you'd first have to explain to him the workings of petrochemistry (assuming he'll listen to your ramblings at all). Oh, and you'd better be an expert in petrochemistry and engineering in general.
• A very short story Ask Caesar by Yevgeny Lukin and Lubov Lukina is an attorney's speech in court. His client is accused of attempting to change history by teaching modern science (up to quantum physics) to Cro-Magnons. "But did it change anything? No." Except for some insignificant details, like the fact that Gaius Julius Caesar has been diced with lasers.
• Doctor Who New Adventures
  • In Just War, an incautious time traveler accidentally gives the Nazis a technological leg-up in the 1930s, resulting in them developing stealth bombers in time for World War II.
  • In The Room With No Doors Joel explains to a 17th century Japanese warlord how to turn a loom into a calculating engine. He's surprised at how quickly the warlord catches on, and comes up with uses for computers that Joel thought he'd have to lead up to.
• Doctor Who Missing Adventures
  • In State of Change, a complex chain of events result in an exact duplicate of Ancient Egypt acquiring knowledge of advanced technology, developing zepplins, electric lights, radio telegraph and nuclear power in just over thirty years.
• A fantasy version is introduced in Guardians of the Flame where Lou Riccetti's wizard character renounces his magic only to start using his engineering knowledge to overturn Medieval Stasis in their fight against slavery. Predictably, the opposing factions, although not privy to the details of things such as how to make gunpowder, find ways to adapt the technology through magic. In fact the slavers manage to make some water-powered rifles which partly work by a spell.
• Time Scout: Sort of. One downtimer gets his hands on uptimer materials and eventually discovers his way through the gates to La La Land.
• TimeRiders:
  • Time Riders has a man intentionally travel back to 1941 a) to give Hitler a ton of future tech, b) to convince Hitler not to invade Russia and c) to take over Nazi Germany himself. In the end, German steamrolled most of Europe and a good deal of the USA in twelve years, with Russia and China next on the schedule. Hovercrafts and pulse rifles tend to give you an advantage.
  • This also happens in Gates of Rome. Project Exodus, launched from the 2070s, involved aiding the Roman Empire in changing history for the better with guidance from the future, firepower, hover boards and the most advanced support units ever created. Unfortunately, that backfired when the Romans decided to ditch the help and just keep the tech.
• Greg Egan's short story "Oracle" does this, with the interesting twist that the "distant past era" is in fact none other than 1950s Britain; the time traveler's main objective is actually to rescue a No Historical Figures Were Harmed version of Alan Turing so that he can jump-start technological progress (apparently, the time traveler's universe, which is heavily implied to be our own, did not progress fast enough to avoid catastrophe.) Therefore, in addition to secretly promoting social changes, such as tolerance of homosexuality, she also gives the Turing-Expy knowledge from the future and good relations with other workers, so that they invent technology even more advanced than what we have in the 21st century, as well as a Theory of Everything.
• In Michael Swanwick's Jack Faust, Faust is a scientist rather than a sorcerer and Mephistopheles is a misanthropic Sufficiently Advanced Alien rather than a demon. Mephistopheles gives Faust access to all the accumulated scientific knowledge of the next several centuries, ushering in the Industrial Revolution and, eventually, a World War many hundreds of years too early.
• Referenced/averted in the Tennis Shoes Adventure Series — Maegen decides that radios would be useless, and brings mini chocolate bars and ball-point pens to trade to the Romans instead.

A group or community is transplanted.

• The Islander Trilogy by S. M. Stirling. The island of Nantucket is whisked into 1250 BC, and must contend with Bronze Age cultures and their own crop of power-hungry renegades. This one does contend with language difficulties, uptime diseases, and so forth; the Nantucketers manage to wipe out huge numbers of Native Americans before they even realize what's going on, because the first party sent to the mainland contains someone with a sniffle. Their language difficulties are moderately eased by the fact that the languages of Europe are, at that point, much closer to still being "Proto-Indo-European"...
  • Also helped by Nantucket being big and upscale enough that having a professor of ancient languages on it at the time isn't ridiculously improbable.
• The Assiti Shards milieu by Eric Flint and others. Cast-off shards of transdimensional alien "art" bombard Earth and transpose large chunks of it with other times and places. Several alternate histories are planned in this meta-setting, including Time Spike (several separate Shard events deposit a modern maximum security prison, the Cherokees on the Trail of Tears, a band of conquistadors, and multiple pre-Columbian Indian settlements into the Cretaceous), 1776 (the armies of George Washington and Frederick the Great both find themselves in ancient Rome during the Crisis of the Third Century), and By Any Other Name (the Assiti themselves make unwilling contact with Elizabethan England), but only two have seen any publishing. The first one has, however, seen a lot:
• 1632 and its many, many sequels. The West Virginia coal-mining town of Grantville is translocated to southern Germany in the middle of the Thirty Years' War, utterly shattering the power structure and world view of Reformation Europe. Once again, this setting deals with language and diseases fairly well. It's also impressively realistic about how technology works: while some advanced technology comes with them, their biggest influence comes from modest improvements that can be built from the existing technological base, like replacing matchlock rifles with flintlocks.
• Parodied repeatedly by John Scalzi in Scenario #6 of his short story, "Missives from Possible Futures #1: Alternate History Search Results".
• The Axis of Time trilogy by John Birmingham. World War 2.1: Weapons of Choice, World War 2.2: Designated Targets, and World War 2.3: Final Impact. A multinational naval task force from 2021 is sent back to World War II, where it (literally) impacts with the American fleet steaming for Midway. The consequences are extremely far-reaching.
  • And there's even a nod to The Guns Of The South in that while the up-time multinationals can easily reproduce the AK-47 and "low-tech" (for the early 21st Century) gear, their more advanced devices can't be duplicated because the composites, chemicals, or specific materials can't be manufactured with 1940s-era equipment.
    • Not just the uptimers. The Soviets manage to do the same by studying the databanks aboard the Vanguard. The Nazis and the Japanese also make some small advances, but not many.
    • Also, the American and British versions of the AK-47 feature underslung grenade launchers, making them much more effective in combat. By the third novel, all the uptimer ships and troops are forced to "downgrade", as their ammunition has run out. This "downgrade" is still superior to what was available in the 1940s, though.
• The Destroyermen teach their initially Bronze Age Lemurian allies how to build and use pretty much anything they can dream up. They have a good reason for this: the series' Big Bad is a race of dinosaur descendants that think humans and Lemurians are crunchy and good with ketchup. So far the technologies transferred include (in roughly chronological order): modified Greco-Roman infantry tactics and weapons, gunpowder and cannons, oil drilling, the Bessemer process, steam propulsion, muskets, electricity, seaplanes, and of course, radio.
  • On the other side, the transplanted Japanese end up in the hands of the Grik, and are forced (in some cases, no forcing was necessary) to teach them new things. Several books later, the Grik start building seagoing ironclads, blimps dropping kamikaze bombs, muskets of their own (albeit cruder because of the Griks' claws), and artillery (including anti-air variants).
• Mateo from Driftless Wormhole has a similar problem to Paul Twister's listed above. He can describe science and technology from his own society in broad strokes, but he has has trouble nailing down the details that would allow anyone to actually build any of it.
• In the first book in the Honor Harrington series, the Havenites introduce Civil War-type firearms to some of the natives of the planet Medusa, who are at a Bronze Age level of technology. Their plan is to have hordes of Medusans armed with primitive firearms, not to mention hopped up on a combination of religious fanaticism and the local equivalent of PCP, massacre the human enclaves, and convince the Manticorans to abandon the planet completely, giving Haven the opportunity to move in. They get found out, and the Medusans run right into a force of Royal Manticoran Marines, but the Manticorans note bitterly that they now have no choice but to introduce the weapons to the more friendly Medusans, so the Medusans can defend themselves. The long-term consequences of this are not shown, as the series never revisits Medusa.
  • A variant occurs in the second book, where the Manticorans introduce advanced technology to the (relatively primitive) planet Grayson, while the Havenites do the same with Grayson's fratricidal sister planet, Masada. Here, the tech gap is much narrower, as the Graysons and Masadans are well ahead of modern Earth, just way behind the Manticorans and Havenites. In the climactic battle, the Masadans have hijacked a Havenite warship that would normally make mincemeat out of the Manticoran ships, but the Masadans don't know how to properly operate it. In later books, the Graysons catch up with the Manticorans, to the point that the Grayson Space Navy is probably the fourth best in the galaxy (and the Andermani and Havenites only win by sheer numbers).
  • The Novella Dark Fall introduces a Lost Colony who regressed to a hunter gatherer stage and took 1500 years to regain primitive steam engines. Haven's discovery and uplift of Calvin's Hope produces bolthole, a secret industrial center able to outproduce even the Manties.
• The Last Day of Creation by Wolfgang Jeschke. The protagonists are stranded five millions years in the past, and while Neaderthal man proves willing and able to learn to use 20th century jeeps and firearms, when the suggestion of giving humanity a technology jump is raised, they conclude that none of their efforts will amount to anything in the vast abyss of time to come. One reason they're stranded however is because alternate timelines have been created—it's suggested by a more effective version of this trope, in which a small team of military advisors with modern weapons time travel to a crucial point in history, ensuring that Cortez is ambushed by machine guns or Columbus gets roasted with napalm.
• A non-time-travel example in The Lost Regiment. After the Battle of Gettysburg, the 35th Maine boards a ship along with an artillery battalion, and the ship is transported by a Negative Space Wedgie to another planet (the two moons are a dead giveaway). There, they find numerous city-states founded by humans who have been transported there throughout history. This includes ancient Russians (the first culture they meet), Carthaginians, Romans, Maya, and others. They also find out that the rulers of this world are 10-foot-tall Human Aliens divided into several hordes that are engaged in never-ending circles around the planet at different latitudes, demanding and receiving tribute from the human city-states in the form of crops, materials, and people for food (their word for humans is "cattle"). It's not long before one such horde, the Tugars arrives to collect their generational tribute and put the newly-arrived "Yankees" in their place. After helping the Russian peasants rise up against the boyars and the church, the Americans resolve to turn the city of Suzdal into a modern (i.e. Civil War-era) industrial power with a modern army with firearms. Unfortunately, they only have a year before the main body of the horde arrives. Many of the soldiers are former factory and mine workers, so they are familiar with the methods of industrialization. However, making Civil War-era rifled weapons requires precision tools, so they, instead settle for Revolution-era muskets and smoothbore cannons. They even build an observation balloon and a working locomotive. By later books, they move on to seagoing ironclads.
• Played with in Julian May's Saga of the Exiles. A time portal is created that can only send people back to a specific place around 6 million years ago. They attempt to avert this trope by banning the travel of any technology or psychic powers that could affect the future/present in any way, and forcing any women to be sterilized. However, it all goes a bit wrong when it turns out Earth of that time has been colonized by aliens from another galaxy, who can reverse the sterilization and breed with humans (their Living Ship chose Earth specifically for that reason). Although the aliens have some advanced technology, they were largely living in a somewhat cleaner medieval society before humans arrived and started industrializing things. However, it turns out that even though sterilization could be reversed and humans started breeding (with each other and the aliens), there were no alterations to the future. It's strongly implied that the aliens are responsible for Celtic mythology and for humanity's strong psychic potential, but all traces of technology and civilization were gone before the start of recorded history.
• Happens in John Barnes's Timeline Wars trilogy (Patton's Spaceshipe, Washington's Dirigible, and Caesar's Bicycle). The series is about a pair of alternate universe factions that are waging a multi-dimensional war against each other by going to different alternate Earths and recruiting a group of the natives of that world to their side to fight. In the first book, the main character winds up in a world where the Axis won World War 2 thanks to being given what was effectively 1945 technology in the 30s, so they had jets and more advanced tanks and battleships. He ends up helping them build spacecraft, nuclear bombs, and laser cannons. The second and third books feature similar alternate universes, as seen in the titles.
• In the novella Veritas by Robert Reed, three retrofitted cruise ships loaded with equipment and technical experts are sent back to Ancient Rome immediately after Caesar's assassination, and usurp power after a show of power by disintegrating a section of the city wall instantly by warping it to the paleolithic era. They set about raising Rome's level of development by establishing relationships with powerful families and giving them monopoly rights on the production of high-tech goods. Fifty years later, their technology is a mishmash of 19th- and mid-20th-century tech. The crew of the cruise ships were thoroughly screened to prevent modern-era diseases from reaching pre-penicillin and pre-vaccination Rome, though they inadvertently bring HIV with them, with is ravaging the population.
• The Wandering Inn: Ryoka, who was teleported from Earth to a medieval fantasy world, has plenty of knowledge about Earth's technology, but she's so afraid that the knowledge will fall into the wrong hands that she can't reveal any of it. This dilemma forms one of the Myth Arcs, as Earthers gradually share or reveal technologies and ideas but wrestle with the possible harm they might do by creating firearms or engines.

Live-Action TV

• The time travel arc of Galactica 1980 is constructed about this. Realizing that Earth's technology would be insufficient to repel the Cylons were the Galacticans to reveal themselves to the Earthmen, radical scientist Xavier researches Earth's past and decides that the best course of action to advance Earth's technology is to give the Nazis rocket technology which would allow them to win WWII. Fortunately the heroes have followed him to the past and thwart the attempt.
• The Beverly Hillbillies is as close you can get to this without using time travel — seeing as the Clampetts lived like it was still the 19th century before becoming wealthy (one truck among them, horse travel still being common in their region, and one phone in a 40-mile radius being the most advanced they had it), the sudden culture shock of moving to a modern Beverly Hills mansion with all the modern furnishings allowed for some real oddities.
• Doctor Who:
  • "The Time Meddler": The Meddling Monk was planning this, talking about how Shakespeare would get to write for the TV.
  • In "The Time Warrior", Linx the Sontaran plans to give a medieval warlord Irongron firearms. Though unlike other examples of this trope, it's simply a means of him buying off while Linx repairs his spaceship. Also, despite his own advanced technology, Linx has no intention of giving Irongron any more than the bare minimum to impress him in the form of crude black powder firearms. The Doctor still worries about the long term effects of giving these warlike humans advanced weaponry before their time.
  • "City of Death": Scaroth's spaceship explodes on primordial Earth, splitting his consciousness into multiple pieces scattered throughout Earth's history. Each instance guides the development of humanity so that his final self can have time travel technology in the mid-20th century and he can go back and prevent the explosion, (which also happens to be what sparked the evolution of life on Earth. Oh well!)
  • Downplayed in "A Town Called Mercy": An alien scientist sets himself up as a citizen in a wild west town and ingratiates himself with the locals by installing electric lamp-posts, which the Doctor notes are about 10 years ahead of their time.
• An accidental example in Journeyman episode "The Hanged Man", when Dan accidentally leaves a digital camera in 1984. He goes to work at the newspaper and sees holographic screens and video-playing paper. It's all well and good until he also finds out that his son was never born because of a malfunction with the new systems at work when he was supposed to have sex with his wife. Instead, a daughter is conceived later. He ends up going back and stealing the camera (well, it's not really stealing, since the camera is his anyway) from a tech company in the process of studying its microchip.
• In Joy of Life, the main character, Fan Xian, a modern person reborn in imperial China, occasionally does this, reinventing things like a humidifier and soap, but to his surprise, when he tries to patent some of these "new" inventions, his father tells him his mother had already invented these things. This is because Ye Qingmei was also a "modern" person.
  • Also applies to the gun Ye Qingmei brought from the "Temple"
• In one Key & Peele sketch, "Congressman Peele" begs the other Founding Fathers not to sign the Second Amendment because of the potential for future massacres. When they laugh at his warnings, he announces he is from the future, draws a pair of MAC-10s, and blows away the Amendment and the table it's laying on to make his case. The MAC-10s disappear from Peele's hands in a flash of blue light, but when one of the Founding Fathers audibly expresses his amazement at the destruction wielded by the "muskets" and a second one pulls out a piece of paper to make a sketch of them before he forgets, a pair of nasty high-tech looking weapons appear in place of the MAC-10s.
  Congressman Peele: [looks at weapons] Damn it!
• The second Legends of Tomorrow episode has a small piece of Ray's Atom suit be knocked off during a fight in 1975 Norway. Savage ends up finding it and ordering his people to reverse-engineer it. After getting back to the Waverider, the "legends" are told by Rip and Gideon that, with the advanced technology, Savage is projected to start his Take Over the World plan earlier. Central City is shown to be burning by 2016 (presumably, Barry couldn't stop it). According to Rip, this is only a projection, but it will become a set future once the reverse-engineering is complete.
• Life on Mars (2006) has this in abundance. Sam is always trying to introduce modern policing methods, apply his future knowledge and so on, much to the ire of Gene Hunt. As well as other non-police-related things (having a TV in a pub, chicken in a basket, etc.).
• Alex does a fairly simplistic version in Ashes to Ashes (2008), when in order to smoke out a suspect from several possibilities without arousing suspicion, she decides to (in her words) "invent speed dating twenty years early".
• In Misfits an old Jewish man goes back in time to kill Hitler. He fails and drops his mobile phone, which enables the Nazis to develop better technology and win the war, taking over Britain. Kelly gets the time travel power and is able to get the mobile away from Hitler, along with beating him up.
• Subverted in the Quantum Leap episode "The Leap Back." Ziggy's handlink accidentally travels back to 1945 with Al after the simo-leap, but it doesn't work because Ziggy doesn't exist yet so there's nothing for the device to link up with (much like how a mobile phone wouldn't work in an era before satellites). Indeed, when that episode's love interest is seen punching buttons on the dead handlink, Al comments that the device probably won't work again until 1999.
• Star Trek:
  • Star Trek: The Original Series touches on this in "A Piece of the Action", twice. The Iotians' culture was based around a book on 1920s Earth Chicago mobs, left behind by a previous starship. Then, near the end of the episode, Bones sheepishly admits that he accidentally left his communicator on the planet, which contains a unique piece of technology that Spock predicts will accelerate Iotian technology even further.
  • Star Trek: The Next Generation did this in the episode "A Matter of Time", where Berlinghoff Rasmussen, an "inventor" from the 22nd century, traveled to the future to steal technology which he could then reverse engineer and subsequently sell for profit.^note Rasmussen stole his time machine from 26th century time travelers, but he didn't fully understand how it worked, which limited his ability to fully utilize it.
  • In one episode of Star Trek: Deep Space Nine, Quark gets the idea to do this after being thrown back into the mid-1900s. However, his initial target (chosen out of convenience) is the American military, who are more suspicious than receptive, making Quark suddenly very eager to return to his own time.
  • Star Trek: Voyager lifted this plot for the "Future's End" two-parter. A captain of a Time Ship from the 29th century gets stranded on Earth in the 1960s. A camping hippy finds the crash, and reverse engineers its technology to completely invent the Computer Age, draw out all the profits he can make from everything from the ship (and continually revolutionize his own revolutions) for as long as possible. To be sure, he only manages reverse-engineer the basic things and lacks the knowledge to understand the more complex pieces of tech (e.g. shields, weapons, warp drive, temporal drive, etc.).
  • In the Star Trek: Discovery episode "The Red Angel", Burnham learns that her parents believed this trope to be true, citing a number of sudden leaps in technology through the history of several civilizations. Others were skeptical and kept offering plausible explanations for the advancements that did no involve time travel. Of course, they couldn't possibly know about Henry Starling and Chronowerx Industries (see the Voyager example above) or else they'd know they were at least partly right.
• Terminator: The Sarah Connor Chronicles: Each faction of time travelers is trying to shape the development of technology in their own way. The resistance is assassinating developers of A.I. that they think could lead to SkyNet and the various machine factions are trying to either pre-stage resources for the war and facilitate SkyNet's creation, or in the case of the rebel machines led by the T-1001/"Catherine Weaver" to develop their own A.I. to oppose SkyNet.
• Timecop: In "Rocket Science", a German yuppie travels to the '40s and introduces enhancements to Nazi technology. Slightly justified in that he had already done all the research he needed in order to improve their tech. When Logan goes back (again) to stop him, he walks into his lab, where a German scientist is trying to figure out how to work the yuppie's laptop. The Nazi is obviously having trouble with a concept such as a portable computer. Logan simply smashes the laptop and leaves. Of course, he leaves all the pieces in the past, which means there should still be a potential for reverse-engineering it.
• Warehouse 13 discusses this and The World Is Not Ready at the same time: Were Thomas Jefferson to discover a radio in his time, he'd just lock it away until he worked up the nerve to take it apart ^note Of course, Mr. Jefferson would have good reason to think it was something demonic: Without signals to receive, the radio would give off a lot of very evil-sounding empty static!.
• The Quantum Leap episode "Salvation or Bust" downplays it a bit, but has Ben remark to Addison how they're able to use their 21st century know-how to punch up the 19th century town's defenses.

Podcast

• A major plot-point in the Twilight Histories episode “The Winged Victory”. You become stranded in a world where Rome’s Greek provinces successfully revolted. You try to develop enough technology so that the Greeks will be able to defend themselves when the Romans return to try to conquer them. Ironically, given the trope title, you also attempt to keep the advanced technology out of Roman hands.

Tabletop Games

• GURPS has included the rules for doing this since the first edition. And it happens fairly often in Infinite Worlds despite ISWAT's best efforts, though with alternate realities instead of the past or other planets.
  • And there is of course Johnson's Rome, where a MegaCorp took over a Roman parallel world after ISWAT clerk forget to Read the Fine Print while giving a commission for operating there. When everyone realised what exactly they've signed, the place was already irreversely tampered with wide-scale access to high tech and turned into a trans-dimensional tourist trap.
• There's a Teenage Mutant Ninja Turtles & Other Strangeness adventure in which a time-traveling Southern man buys a bunch of automatic weapons with the intention of giving them to the Confederacy. The players are supposed to stop him.
• In early editions of Warhammer, it was possible for weapons and people from Warhammer 40,000 to find their way into the Chaos Wastes. This is less damaging than most examples, since there's no way to jump-start an industrial revolution from an object that takes stupidly-advanced tech to make. Especially considering that the primary engineers and technicians of the 40K setting are so reliant on barely-understood and religiously revered ancient tech that they themselves nearly constitute a Cargo Cult.
• You can send resources (including peoples) from the future in the boardgame Anachrony. You can later travel back in time and reimburse those resources, or erase your debt by other means (mostly when you get hit by a temporal anomaly).

Video Games

• Might and Magic VII features a somewhat... complicated non-time travel version. One group aims to restore contact with the Ancients, which (since the loss of contact caused the fall into barbarism in the first place) could be seen as a roundabout way of getting someone better equipped than you to do this. The other group claims to have this as a goal for the Lost Colony you are on, and in a limited fashion does so in their (non-canonical) ending... but that might be more realizing that even with superior technology, you need an army to use that superior technology, lest you be swamped by the thousands of dragons and assorted powerful critters out there. Throwing things for a loop is that both factions themselves come from another primitive world, and have only gotten a better grasp on Ancient technology than the locals through the circumstances of them getting there.
• This is essentially the whole plot of TimeShift. A scientist, Dr. Krone, steals a time travel suit his company had developed, disappearing into the past, and setting the building to explode to cover his tracks. The protagonist, another scientist, attempts to follow him in a less reliable prototype suit. He arrives in 1939, several years after Krone's destination, and he finds that the '30s look quite different than in the history books. Krone has leveraged his knowledge of future technology, using it to form a new, dictatorial government with himself at the helm. He's also fast tracked technological development, turning the '30s into a Steampunk Dystopia, complete with battle zeppelins and giant mechanical spiders.
• Cheating on tech levels in Paradox Interactive games can lead to things like handing repeating rifles to the Byzantine Empire during the siege of Constantinople in the fourteenth century.
• The plot for World of Warcraft's fifth Expansion Pack, Warlords of Draenor, is kicked off by Garrosh Hellscream going back in time 35 years to Draenor (the Orcs' homeworld) and introducing to the tribal hunter-gatherer Orcish clans the vaguely steampunk technology built by his Goblin mercenaries in order to create the Iron Horde; with the already military-oriented Blackrock Clan making good use of the Goblin tech to create battleships, siege engines, and even a vast railway network to deliver reinforcements and war material to multiple fronts.
• The final level of Empire Earth involves Grigor II going back in time to modern-day Russia (the first level of the Russia campaign, in fact) to give Grigor nano-age tech, allowing Novaya Russia to rise to power far earlier, before Grigor's health deteriorated, and the players stopping him.
  • From the same level, Molly Ryan, spy from the same future as Grigor II, instructs Grigor II's enemies in how to train spies for a deliberate technology theft to turn the tide of the battle.
• Some of the levels in Bill and Ted's Excellent Video Game Adventure involve this, like giving Jesse James an uzi and Cleopatra a credit card.
• This is, in the background, Kane's entire schtick in the Command & Conquer series. Kane is an alien stranded on Earth far back in its distant past, and much like the Niven example earlier (albeit with a far more hands-on approach), commits to the long game, gradually increasing humanity's technological prowess to perhaps find a way home; this pays off when the arrival of Tiberium allows him to launch an endgame plan to attract the alien Scrin to the planet and get humanity, using technology he's largely responsible for, to destroy them for him. He then performs a final bootstrap off of Scrin technology to return home, taking some of his followers with him.
  • The Backstory for the Red Alert 3 mod Corona shows that in an attempt to Make Wrong What Once Went Right in favor of the Empire of the Rising Sun, Crown Prince Tatsu traveled back to The High Middle Ages ( by reverse-engineering the Soviet time machine rather than destroying it, as was in the original game) and provided the Mongols with modern Imperial technology, giving the Mongols a disproportionate advantage that allowed them to conquer Europe in a Curb-Stomp Battle. But in an ironic repeat of the Soviets' actions, Tatsu's meddling with the space-time continuum had inadvertently caused the rise of the Celestial Empire and adding a new warring faction to the already-chaotic Mêlée à Trois between the Allies, the Soviets, and the Empire of the Rising Sun.
• A common mechanic to help a race develop in Millennia: Altered Destinies is to take something they've recently invented and give it to them a few centuries earlier.

Web Original

• Rome, Sweet Rome examines whether a modern U.S. Marine Expeditionary Unit could overthrow the Roman Empire in the reign of Augustus (23 B.C.).
• Lampshaded and discussed by Paul Twister, regarding being stranded in a fantasy world:
  I have no illusions of raising this place to a 21st-century standard of living, or even a 20th-century one. I'm no Connecticut Yankee, just a Seattle Geek who happens to know a few things about the way things work. ...For example, I know that spinning a magnet around inside a coil of copper wire produces an electric current. But how strong of a magnet? How big does it have to be, and how fast does it have to spin, before you get anything useful? Does the size of the coil of wire relative to the magnet matter? Does the number of loops in the coil matter? We're rediscovering all these things from first principles.

Western Animation

• Justice League: In "The Savage Time", the immortal Vandal Savage sends a laptop with a message on it to his past self, the information on the laptop allowing the past Savage to take control of Nazi Germany and lead them to win World War II.
• Invoked by Venger in an episode of the Dungeons & Dragons (1983) cartoon. Venger uses his magic to kidnap a jet-fighter pilot and his jet from the future, and a German WWII Luftwaffe pilot. His plan was to send the Luftwaffe pilot back to WWII with the futuristic jet, so Germany wins the war, preventing the birth of the heroes. Fortunately, his plan failed, because the German pilot pulled a Heel–Face Turn after meeting the heroes, who convinced him into not going along with the plan.
• The Family Guy episode "Life of Brian" begins in a present-day America ruled by the Native Americans thanks to Stewie traveling back in time and giving them automatic weapons. For whatever reason, this also meant that the country had next to no advancements in science, technology, music, or infrastructure beyond what the Native Americans were familiar with during their time period.
• Parodied in Free Birds, when Reggie offers pizza to the attendees of the first Thanksgiving, preventing turkeys from being on the menu on an annual schedule.
• One episode of Time Squad has an unintentional example. Kublai Khan arrests Buck and takes his raygun magazine, then uses the blueprints in the centerfold to make a BFG.
• Inversion: Tom Terrific and Manfred are in the old West during the California gold rush. Tom tries to turn himself into a helicopter but it doesn't work because helicopters hadn't been invented yet.
• In Dave the Barbarian, a nerd from 1994 gains the power to travel through time and attempts to use modern technology in the ancient past to Take Over the World. His nearest success was to get people in the past addicted to video games and then bribe their servitude with batteries.

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