Let's look at pseudo-anachronistic technologies in fantasy fiction (with a TTRPG lens as usual, but I think this also mostly applies to other media).
When Arneson invented the first fantasy roleplaying game, he incorporated numerous science fiction elements. This could be viewed as weird rough edges of what would bloom into the greater hobby, but it was also a product of the concurrent boom era of pulp fantasy and pulp science fiction. Most people coming to D&D and its burgeoning successors could be assumed to have an interest in those kinds of stories. Science fiction aspects (machines, martians, rayguns, etc) stayed in early D&D and the emerging fantasy TTRPG traditions for a while before dying off and it's easy to imagine an alternative pathway where that was the default today. In reality though, in contrast to these roots, 'classic' fantasy is now regarded as a set of tropes which include a setting's technology conforming to a certain band of real-world history and geography.
Interestingly, those tropes are imperfect: they deviate from that implied band of technology in a few particular ways.
Pseudo-anachronism: Or, how we can "know" that Elrond doesn't own a skateboard
What do I mean by 'pseudo-anachronism'? Well, just 'anachronism' doesn't work; it's a word that only applies to historical real-world settings. It's Ancient Romans wearing wax lips and wristwatches. It's Kamakura shoguns carrying shotguns and sherrif badges.
'Anachronism' doesn't apply to fantasy worlds. But there are 'classic' fantasy tropes: default values, as it were. Many settings are designed as if they mostly conformed to certain real-world historical settings, so that players' brains automatically fill in the gaps of what 'ought' to be there. And to drill down into 'certain real-world historical settings', classic generic fantasy tends towards vaguely Late Middle Ages or Renaissance European pastiche. (There's an argument that this particular imagined pseudo-historical window represents a drift towards a later period from the initially D&D roots which blended pseudo-Arthurian jousting-and-castles with Hyborian Age ancient sword-and-sorcery, but nowadays that 1300s-to-1600s Western European default is quite strong in stodgy 'classic' fantasy.) Game masters and players alike will tend to fill in any blanks with what they understand to be a pre-industrial technology level beginning at clocks and the three-field system and ending at huge ruff collars. Then add to the mix a melange of societal assumptions drawn from modernity and pop history, seemingly divorced from available technologies.
So in a 'classic' fantasy implied setting, there is an expectation of a certain tech level. If it turns out that, say, consumer plastics exist, players won't think "oh, these people happen to have plastics technology". They'll think "huh, I wonder what unique magic is producing plastics". Or more cynically, "huh, that's stupid and immersion-breaking."
Nowhere in Tolkien's corpus does he write that Elrond doesn't own a skateboard. And yet we can confidently state that to be true. That's the essence of pseudo-anachronism.
Nerdbait The curse of knowledge
If you're like me, then when you know a topic well, it's grating to see it portrayed badly in fictive media. It may even feel like the more you know about a subject, the worse and more common this problem is, and the natural/cynical conclusion is that pretty much all media only ever gets things right on accident but you're only equipped to notice it when it happens within your domains of interest.
I've certainly found that some of my interests (historical technologies) have ruined some quite major media works for me. Fortunately in the case of my favourite hobby (fantasy TTRPGs), all you need to do is work out what's bothering you and then tweak the world (in self-consistent, verisimilitudinous ways) so that it actually makes sense within the setting.
It's nice when things are self-consistent. And it helps at the table, because players appreciate it when things hang together, too:
Every time players discover that some part of their fantastical world is more logical and organized than they’d given it credit for, their faith in the quality of the GMing, strength of the worldbuilding, and reach of the GM’s imagination surge forward. They’re more inclined to think themselves about how the game fits together–they’re more inclined to think about what NPCs would do, about how the gameworld will react, than plan in mechanical and metagame terms.
(From a
slightly older article but a short one worth checking out if you're into cases of fantasy verisimilitude)
Individual pseudo-anachronistic technologies
So, we're left with a question: what kind of stuff "shouldn't" be in the vaguely Late Middle Ages / Renaissance European default setting of 'classic' Western fantasy? Let's take a look at five common pseudo-anachronisms and, rather than just flagging them for removal, come up with some in-fantasy-world reasons to justify allowing them.
Modern locks and skilled lockpickers
For many people, Skyrim or something like it is the archetypal fantasy 'locks and lockpicking' experience. You (1) pop in a torsion tool to keep pressure on the barrel, (2) apply your skill to fiddle around with a lockpick in the keyway, and (3) the lock opens. This is also implied in the fiction of most fantasy TTRPG/novel settings: the roguish character needs both the necessary skills, and the sophisticated tools, to pick a lock.
Here's the problem: skill-based lockpicking with clever tools is really only necessary to subvert a specific kind of lock, which I will call a 'modern pin tumbler lock'. It's a tumbler with a stack of pins whose variable height at the shear line and rotating barrel mean that pins must be set to the exact height that the key is designed to lift them to. And it's a kind of lock that was only invented, and entered use, in the late 1800s.
Earlier locks were of two main types. First, there were ancient pin-based locks, but their pins couldn't be lifted 'too high'. Even a well-designed one could be defeated easily by putting a bent rod or stick in the keyway and pushing all the pins up. (A poorly-designed one that didn't protect the pins could be defeated in a single motion by putting anything in the keyway.) You could completely master subverting old pin locks in well under an hour, and you don't need special tools for it.
The second type, and the best lock technology for thousands of years, was a warded lock. This has complex 'wards' (metal shapes) meant to prevent the wrong key turning in it. A warded lock can be defeated by a skeleton key (a filed-down regular key). Picking a warded lock therefore amounts to using a big bundle of 'tryout keys' and if they failed, trying various bent rods until one was the right shape to move the latch or bolt. Again, lockpicking before the advent of the modern pin tumbler doesn't require much skill, so we have a pseudo-anachronism.
We'd like huge fiendish fantasy traps and complicated locking mechanisms with poison needles artfully hidden in them and cunning thieves with bundles full of specially-made picks, though. So can we say that a modern pin tumbler lock could have been invented in a much earlier technology level?
The idea for the modern pin tumbler doesn't seem like the tricky part. Ideas can be justified as coming from anywhere at any time. The little springs in the key stack might be tricky, as is the overall complexity of the mechanism. You need (1) good metallurgy (so bits don't break or bend), (2) fine engineering tolerances (so bits don't fail or jam), and (3) good manufacturing processes (so the key actually works and the lock doesn't have other security flaws). You also arguably need to keep the skilled labour cost down, at least to the point where wealthy people with things they want secured might invest in a lock instead of a magical solution. I think all of these are within striking distance of your classic fantasy world, as are the more epic extensions to huge fantastic locks, trapped locks, etc. In particular, the setting likely has supernaturally clever people with small fingers and an affinity for metalwork - gnomes and/or dwarves.
There's also an alternative. Maybe nobody's invented the modern pin tumbler lock, but there's still skill-based lockpicking, because fantasy metallurgy allows for entirely new types of lock. Fantasy loosens the constraints on the laws of physics: we can imagine particular metals that can pass through each other to a certain depth, mechanisms that magically seize up in the presence of common key metals, enchantments that are sensitive to the colour of things that get put in the keyway, and so on. Lockpicking could be a massively skill-based art without the actual locks being very mechanically advanced!
Large glass panes
Many classic fantasy settings 'get this right' but others don't. In general, a window in the form of a sheet of glass large enough to look through, and clear and flat enough to identify what you're seeing on the other side, requires modern technology.
Up until the 1800s, glass panes were distorted rather than properly flat, and not very transparent. They were also more brittle than modern glass, both chemically and because of inclusions and bubbles that weakened it even further. On top of all that, glass was expensive to make! So shutters and curtains were preferred in most buildings, in most places and times (certain cathedrals, palaces, etc notwithstanding).
There were a few methods of making 'flat' glass, mostly based on blowing a globe or tube, flattening it on a metal plate, then cutting it up (crown glass and broad sheet glass). These made for translucent or semi-opaque pieces, not transparent ones, usually riddled with imperfections and distortions. You could grind the best ones down into 'blown plate glass', which would be finer quality and even smaller. To make a window out of the little panes that a glassmaker could produce, you would make 'leadlights', setting a large number of small pieces into a lead (or occasionally ceramic) lattice.
In the late 1600s, 'polished plate glass' was a slight improvement that could make larger and higher quality glass panes by casting glass on a metal surface and then grinding it down, but it was even more costly to produce.
It wasn't until the late 1800s that broad sheet methods were developed into 'cylinder blown sheet' glass which could make larger panes, albeit ones that needed grinding and polishing. From this point, glass could be used as a building material (and became popular after its use in the Crystal Palace of 1851). To get true modern large glass window panes you need the 'float glass' method (molten glass poured onto large baths of molten metal, taking the form of long flat ribbons, gradually cooled and rolled off at the other end). So, nice big windows are a pseudo-anachronism.
The good news: it's possible to make large glass panes using relatively simple metallurgy, hot furnaces, and a truly enormous capital investment. My amateur view is that the fact we didn't get the technology until the 19th Century can be considered an accident of history. In a fantasy world that has glassworkers, metalworkers, and their extremely wealthy patrons, it should be doable, either at incredible decadent kingly expense, or with the help of magic.
Common use of accurate maps
We all know what a map is. A simplified top-down image of a place at a certain scale showing natural and constructed features positioned correctly with regard to their actual positions in space for use as a key tool of navigation and planning. Right? Well, no, that's a modern lens. Many early maps are some combination of (a) allegorical, (b) valuable art pieces for display, (c) neither top-down nor to scale, (d) extremely inaccurate. Despite being ubiquitous in the modern day, reading a top-down map or even understanding what a map means is a learned skill, and not trivially so. Don't expect pre-industrial people to be able to purchase a map, read one, or know what one is.
Cartography generally started out as maps 'of the world', produced by philosophers and scholars to chart what they knew about their universe and/or so their wealthy and powerful patrons could show off. Later, there were maps of territories, and early sea charts. Eventually, local maps of property boundaries were made for gentry, lawyers, and courts.
High-quality terrain maps were only made pretty late in history, driven by demand from military commanders for increased information as the nature of warfare changed. Using maps at all for the purposes of military planning is a recent phenomenon: even though it seems absolutely intrinsic to us now, ancient military commanders and most pre-industrial ones didn't use them at all.
It must be emphasised that people just didn't think in terms of top-down map-like views like we do. Navigation was landmark-based. The central navigational tool for armies was knowledge of the network of known major roads and locally-known minor roads and paths, i.e., institutional knowledge plus scouts and local guides. Not maps. The central navigational tool for civilian travelers was itineraries (codified routes between multiple settlements, usually major cities / ports / pilgrimage destinations), i.e., written or memorised lists of directions, supplemented with asking locals. Not maps. At most you might see sketch images of some terrain features you were navigating by, or a lengthy itinerary might be written on top of a crude map of the continent as illustrative backdrop.
Maps (as local navigation aids) could have been an extremely useful tool for pre-industrial merchants, sailors, military commanders, property owners, and explorers, and yet, they for the most part neither made them nor used them nor understood the idea. (To that list of occupations we might add: dungeon delvers.)
detailed topographical maps of the sort that hikers today might rely on remained rare deep into the modern period, especially maps of large areas [...] Getting lost in unfamiliar territory was thus a very real hazard. Indeed, getting lost in familiar territory was a real hazard
- ACOUP
But there's so much map-heavy fantasy media that it permeates our vision of the past! I think "fantasy=maps" because (a) a map makes a great visual, (b) Tolkien casts a long shadow, and (c) we end up importing all kinds of modern assumptions. Nevertheless, regular people having access to accurate maps and the skills to read them? As remarkable as it seems, probably pseudo-anachronistic. Here's a crude compressed history (drawn from Wikipedia and some AskHistorians threads like this one):
1200s: First maps for ship navigation (portolan charts). Mostly useful for particular known routes, required a good compass, and weren't much use in working out where you were if you ended up far off course. Note that adequately mapping inland regions is much more difficult than coastlines: travel is both slower and more difficult, there are more features to include on the map, and parts of the terrain are inaccessible or obscured by other parts.
Late 1400s: Latitude starts being measured for the purposes of navigating ships. Longitude is vastly more difficult to measure. Explorers like Duarte Pacheco Pereira (1460-1533) make charts and depict parts of coastlines, but as a supplemental part of a highly text-based, descriptive approach to navigation aids.
Early 1500s: Latitude information starts being included on maps, at least for ship navigation.
1500s: First accounts of battles and larger-scale military movements being planned using maps, as reasonable quality land maps start to become available. See e.g. '[Duke] Cosimo studies the taking of Siena' (set in 1553 and painted ten years after), whose subject uses compasses on a map supplemented by a visual depiction of the city.
1600s-1700s: Land maps slowly become more widespread, but far from ubiquitous; the average person definitely cannot read one and the average military commander may or may not be able to. Local usable maps are mostly 'cadastral' maps, i.e., depictions of the legal boundaries, areas and dimensions of particular properties and territories.
Late 1700s: Longitude can finally be reliably measured for the purposes of navigating ships.
Early 1800s: Government-directed surge of high-quality, detailed cartography for military purposes starts in Prussia. This is probably in reaction to a perception that Napoleon's military successes were information-driven. Something like the modern capacity for (and importance of) topographic map-making and map-reading finally starts to be promulgated across Europe (but still only for soldiers). The perceived importance of knowing the terrain is possibly spurred by some other big-picture changes in warfare like army size, logistics and railroads, the role of artillery, speed of battle, etc.
Mid 1800s: Reliable chronometers become common equipment on ocean-going ships; it is finally the era of both making and using good sea maps.
So, 'owning a map and knowing how to read it' is a pseudo-anachronistic fantasy trope unless you're a learned scholar with an interest in philosophy, a lawyer with an interest in property boundaries, or a wealthy lettered ruler with an interest in territorial boundaries - at least until the Renaissance and Early Modern periods, and even then, the list only expands to 'ship navigators' and 'military commanders'.
Whoof! Well, everyone loves maps, so what's the solution? Fortunately, (a) we can give pretty much any fantasy world a history of large armies and sorcerous or monstrous powers mimicking the role of Napoleonic armies as a driver for accurate cartography, and (b) there's probably already magical flight (and/or scrying capable of mimicking a satellite view). Having a mage with a view from high off the ground means having someone who can make accurate maps without the base of sophisticated mathematics and laborious surveying technologies which you'd otherwise need. In a world where flight or distance viewing is 'cheap', we can expect this to be done just out of scholarly interest and/or for the benefit of local rulers and wealthy patrons, so we don't even need maps to be warfare-driven. Pseudo-anachronism solved!
Metal doodads
Metal is a wonder material. It comes in many different kinds with many different properties, and the tools you can make from it are harder/lighter/more durable/sharper edged/etc. Metal is also precious. In our world, at least, most of the useful stuff is tied up in minerals: iron is abundant but a hassle to smelt from ore, and other base metals are either less abundant than iron, much softer, or both.
A couple of historical notes.
First, I discovered while writing this that doorknobs were only invented in 1878. That's top of my personal list of 'new technologies you would have expected Shakespeare to be familiar with'!
Second, threaded screws are fairly old technology, but they had to be hand-made. High-quality threading of the kind you can reliably join a nut to only came about with 'swaging tools' in the 1850s, so nuts and bolts should be considered modern. In general, early woodworking preferred skilled joinery over nails (because iron was expensive and nails had to be individually made), and in turn preferred nails over wood screws (because it's a nail plus a bunch of incredibly meticulous skilled labour cutting a thread into it). Fantasy carpenters, take note.
This is minor stuff, barely even pseudo-anachronistic, and I think is pretty much covered by the discussion of locks and glass above. Nobody's actually going to be thrown out of the flow if you mention doorknobs. You can also change things up by having useful metals be naturally more prevalent in your fantasy world without even getting into 'standing portals to the elemental plane of iron' and so on.
Explosively flammable lamp oil
Here's a classic fantasy trope: you toss the lantern onto the cobbles and it WHUMPHS into a fireball. You douse the monster in lamp oil and one strike of a torch turns it into barbecue. Fantasy oil is not merely combustible but wildly flammable!
The pseudo-anachronism is obvious if you have a basic knowledge of materials science: pre-industrial people weren't using volatile substances with low flash points for everyday lighting, cooking, and heating. They were using plant oils (mostly olive oil) and animal fats (mostly fish oil or whale oil). To make torches and candles, add pitch, resin, beeswax, and tallow to the mix.
None of those things burn by themselves if you touch a flame to them. All of them have to be heated up a lot before they will catch fire and stay burning, except in the case where they're serving as the fuel for a burning wick.
(Read these three articles and the comments on them for a more full treatment of the topic with regards to original D&D)
To have lamp oil catch like petrol it has to actually be, well, petrol (or something like it). Again, there is no overlap between 'things you can make a room-temperature incendiary weapon from' and 'pre-industrial materials used for domestic fires'. Even when you refine petroleum, you produce some fractions with a low enough flash point to ignite and burn even on a cold day (petrol, notably), but you also get a bunch of other fractions whose flash point is too high (diesel, kerosene, and jet fuel don't burn at room temperature and pressure - you'd have to stop and boil your 'lamp oil' over a fire for a while before throwing these ones).
Alternatively, I guess you could burn particular alcohol distillates, like ethanol, in your lamp. If you had more money than Midas and no fear of fire.
Now, technologies to refine rock oil and distill alcohol were discovered a long time ago, well within the classic fantasy setting era, but these low flash point substances are very labour- and resource- intensive to produce by hand. If you want old timey incendiary grenades on your equipment list, they have to be made of something other than 'lamp oil' and multiple orders of magnitude more expensive than it. There's a few more caveats: early incendiary weapons (e.g., 'Greek fire') seem to have been delivered by catapult or huge portable siphon more often than thrown vessels, seem like they were difficult to wield safely and reliably, and were a state secret. All those objections can be overcome by adding a new fantasy material that works as an incendiary, of course. Fire weapons are cool and well-entrenched in the genre, so I say go for it.
I like the idea of combining the two classic fantasy thrown weapons – holy water and flammable oil – as a single plausible substance. My pick for the 'holy fire' weapon is ethanol: it burns with a mysterious smokeless flame that is very faint and blue, it can be poured on wounds to stop them suppurating, and the incautious imbiber is struck with euphoria, visions, and sometimes a debilitating curse. It's an old technology but costly to get your hands on (because it has to be distilled by a learned sage, using up valuable farm produce in the process). And the concept of extremely evil monsters having a specific vulnerability to 'smokeless flame' is just as cool as the well-trod and curiously Christianity-centric concept of them being harmed by blessed water.
And then also
So that's my notes on resolving pseudo-anachronisms for specific individual technologies in classic fantasy settings.
Now available: Part 2, a scattering of addenda on missing technologies, systemic technologies, and societal features!