A Brief (Social) History of Time

Because I figured we’re overdue for another installment on world-building. As always, this is not a how-to manual, but a survey of the questions that writers should keep in mind when designing a world.

Today’s episode is brought to you by TIME!

It happened in Angen 3, if I recall correctly. On the 28th day of the 4th month, sometime during the hour of the dog, a fire broke out in the southeastern quarter of the capitol and was driven northward by fierce, unceasing winds.

(Kamo no Chomei, Hojoki)

Time is one of the many things that writers coming from a modern perspective have a terrible, terrible habit of taking for granted when they attempt to write a premodern fantasy. Modern notions of the second, the minute, the hour, the day, the week, (the WEEKEND!), the month, often get copy-pasted into fantasy literature wholesale, and often the only concession to this being a non-earth setting is a hasty name change.

(Like: Whoa shit, son! there can’t be a January if this world doesn’t have a Janus, so I’ll call it… uhm… Garsh’kazar? >_>)

As a fantasy writer, one of my preoccupations is how things might have developed differently. So obviously our current calender, with its 28-to-31-day months, 7-day weeks, and 24-hour days is one way that it could have developed, as is proven by the fact that it did, but are there other ways it could have gone? We think of our clocks and calendars as natural and self-evident because that’s what we’re used to, but might some other system work equally well? Or are there real, physical factors in play that would inevitably lead us back to the same calendar? Is there a reason why years have 12 months? Is there a reason why weeks have seven days? Is there a reason for weeks at all?

In short, how do you invent a time system that could have plausibly developed? Or is filing the serial numbers off the Gregorian system the only way to have a realistic calendar?


…the moon.

Seriously, it’s right there! Everyone sees the same moon, its changes are unmistakable and obvious to all, as regular as clockwork. It’s not a coincidence that almost every early calendar hitched its cart to the cycles of the moon — that’s a solid foundation for keeping time. And indeed, if the 29.5-day lunar cycle had correlated at all with a solar year, we’d probably still be using it.

But it doesn’t, and of far more practical importance than the cycles of the moon are the cycles of the sun. People need to know when they can expect the temperature to change, farmers need to know when the annual flooding is going to occur, sailors need to know when the trade winds are going to pick up. The lunar cycle provides a good way to tick off 30-day increments, but the solar cycle is the one with a tangible effect on people’s lives.

So to a certain extent, your calendar does have to be grounded in the physical world in order to be realistic. One year = one full rotation through the seasons, but if your fantasy setting isn’t supposed to be earth, then there’s no reason why it would necessarily be 365 days.

Case study: Kirith Kirin

Jim Grimsley got into some trouble with this in Kirith Kirin (one of my all-time favorite fantasy novels and a gem of world-building) because the protagonist, Jessex, is stated to be 14 years old when he shags the eponymous immortal king. That skeeved a lot of people right the hell out and provoked outrage about pedophilia, etc — but if you look at the appendix and tally up the number of days in each month, it turns out that a year in Grimsley’s world is about a third again as long as ours. Jessex is actually nineteen.

…for whatever that’s worth, because he’s still a teenager shagging an immortal king.

In fact, your calendar is probably not going to be 365 days — not every year, anyway. Because in physical terms, a “year” is the time it takes a planet to make one full revolution around the star that it orbits, which has nothing to do with the length of a “day,” that is, how long one planetary rotation takes.

This is the source of all our calendar shenanigans.

It takes earth 365 days, 5 hours, 48 minutes, and 45.1875 seconds to make one full rotation around the sun. There is literally no way to map that to a fixed number of days.

As far back as the Babylonians and ancient Egyptians, they’d already figured out that 365 days was as close as you could get to a year, but even that was going to stay accurate for only so long, like a clock running just a bit slow. In Egypt this resulted in what’s known as a “wandering year,” where the named months gradually rotated through all the seasons, coming full circle in slightly over 1,400 years. The Babylonians devised a calendar of 19-year cycles, in which seven of the years had 12 months, and twelve of the years had 13 months. If that sounds confusing, it was — February 29th is downright elegant by comparison.

That said, this is your fantasy world, and if you want to make your year correlate precisely to some number of days, that is entirely okay. I doubt readers are going to complain that you didn’t derail the plot to talk about leap-years.

What’s usually a more pressing question is what year your story is taking place in. In the west we’ve become very accustomed to the B.C./A.D. divide and the concept of a year zero — and indeed, come to think of that system as natural, or even the default. But who gets to decide when HISTORY AS WE KNOW IT began? And how are they powerful enough to make everyone else follow their lead? In our world it was the Catholic Church, but if you don’t have a similarly influential, multinational organization in your world, then odds are pretty slim that all the various countries would agree on one particular event as being important enough to anchor the calendar there.

What people did in China and Japan — what they probably did in most places, I suspect — was to reset the calendar with the reign of every new monarch. Such a system meets the needs of pre-modern peoples admirably, because peasants have no need for the dates of events that occurred hundreds of years before they were born. A king or emperor generally lives long enough for their reign to be a meaningful chunk of someone’s life, so you’d know the kings you’d lived through, and probably a generation or so back, and that was perfectly adequate for dating — with precision! — anything that had occurred in living memory.

It’s also useful to keep in mind that no country ever exists in isolation, that there’s going to be economic and cultural exchange with other countries, and that Hegemony Is a Thing. Once internationalization begins in earnest and there starts to be a need for things like an agreed-upon calendar, then whatever system in use by the most powerful country stands a good chance of being the one that everyone else winds up adopting out of necessity. Some places may also keep their own system (I have, for instance, filled out paperwork and had to list my year of birth as “Showa 60″) but they’ll have a working familiarity with the “common” calendar.


It’s not a coincidence that month is cognate with moon, or that nearly every calendar mankind has ever devised wound up dividing the year into 12 months. Even if a month on today’s calendars is completely detached from the cycles of the moon, it was thanks to the moon that 29.5 days got entrenched in our heads as a meaningful unit of time.

So what if you had three moons? WHAT IF YOU HAD NONE??

There is no way to tell, because the only data we’ve got comes from our own history, and there’s no control group. It does speak to an apparently universal human need to divide time into segments more manageable than “years,” and indicates that 30-ish days is a length that works for human cognition.

Case Study: Kirith Kirin again

Speaking of three moons, that happens to be how many the world of Kirith Kirin has — they’re just not on any kind of schedule. It is literally completely random which moon (or moons) is going to appear on any given night. Ditto the stars. According to legend, the moons and stars used to move in accordance with predictable patterns, until their god, out of anger toward humans, broke the sky.

That’s not a major plot point so they don’t dwell on it, but it’s jarring enough to give the reader pause, violating our sense of the laws of nature, and it has some interesting implications. Jessex later theorizes that the reason science developed so slowly there was because there were no natural rhythms in the world for humans to build on.

And if you think that an unpredictable night sky is a physical impossibility — yeah, no kidding. That’s supposed to be a hint that there’s something seriously off about this world.

Some places number their months, some name them after gods, some give them a name descriptive of that time of year. The traditional Japanese calendar has some with obvious names like “Month of Leaves” (August), “Month of Water” (June, when the rice fields flood), plus some weird ones like “Month of Books” and “Priests Running.”

The real point to take away is that even if your solar calendar isn’t attached to your lunar calendar, people have a compulsion to divide time into manageable chunks, and the length of a moon cycle makes a solid and universal foundation for one. And speaking of the human tendency to divvy up time, that brings us to…


Seriously, everyone does it. This is kind of crazy when you think about it, because there is no natural or astrological basis for grouping days into weeks, but people do it everywhere.

Granted, that doesn’t mean they all agree on how long a week is. Our seven-day standard is an arbitrary median, from a collection that averages between 5 days and 10. Whatever number is considered ~lucky~ in your culture is a good bet for the length of their week.

It is also worth noting that our days-of-the-week cycle repeats independently of our day/month/year calendar, but that is not necessarily the norm. Weeks in ancient Egypt were 10 days long, each month was divided into three weeks, and a year was 12 months — which you may notice adds up to only 360 days per year. They had to tack on an extra 5 days at the end of the year and set them aside for religious festivities. Other places distributed those 5 extra days among the months, so that some months had 30 days and some had 31.

The traditional Japanese calendar was also 10 days per week/3 weeks per month. They’re on a seven-day calendar now, but a relic of this survives in the language, that they have a trio of words meaning “beginning third of the month”, “middle third”, and “closing third.” When I first learned that I was like, what’s the point? But of course, those used to just be the words for “first week”, “middle week”, and “final week.” (And they do turn out to be surprisingly useful for indicating a general time. Examples from Wikipedia: “Current temperatures are typical for the jojun of April” or “A vote on the bill is expected during the gejun of this month.”)

The need for days of rest also seems to be a universal human trait, which has generated many diverse justifications for why people are allowed not to work on certain days, but the upshot is the same — people get some R&R. In the Christian west, of course, it was because God rested on the seventh day and people should do likewise. Followers of Mithras were quite happy to support the Christian push to hold Sunday sacred, because they worshipped a sun god. Later, it became useful to have a designated “market day” when other kinds of work were suspended, giving people a chance to rest and to get their shopping done.

In other places, it’s because certain days were considered highly inauspicious for certain types of work, or when specific activities were proscribed — so ironically, it was often the BAD AND UNLUCKY DAYS when you got to kick back and relax. For the Romans, “Saturn’s Day was a day of evil omen when all tasks were ill-starred, a day when battles should not be fought, nor journeys begun. No prudent person would want to risk the mishaps that Saturn might bring.” (Boorstin)

Japan has what’s called the Rokuyou, a six-day cycle in which some days are considered better than others for certain activities. Taian is the bestest and luckiest for everything, butsumetsu is the worst. An interesting one is tomo-biki, meaning “friend pull,” which is auspicious for everything except funerals, because you don’t want the dead person friend-pulling anyone down with them. (No one ~really~ believes in this anymore, the same way no one in America ~really~ believes that black cats and Friday the 13th are unlucky… and yet you can still get your wedding catered dirt-cheap if you’re willing to do it on a butsumetsu day, and most crematoriums are closed on tomo-biki days.)

Similar concepts had been in play well before Rokuyou came along though — as far back as The Tale of Genji (circa 1000 AD), certain days were considered bad for all kinds of random things. That you couldn’t travel, for example, or that you couldn’t travel north, so if you’ve gone to visit a friend who lives south of you, welp, looks like you’ll just have to stay the night! (…This is mostly a plot device to give Genji an opportunity for more sexxing.)

Case Study: French Republican Calendar and Melusine

After the French revolution there was a push to get rid of royalist and religious influences, and one obvious place was in the calendar — replacing the traditional lundi/mardi/mercredi with numbers, and also giving every day a plant or animal affiliation instead of a saint. Except they didn’t stop there, because this was during the push for decimalization and they wanted to establish timekeeping in increments of ten. So they devised a system of 10-day weeks, 10-hour days, 100-minute hours, and 100-second minutes, and gave it a whirl.

It lasted all of twelve years.

The thing is, that system is no less legit than any other, so it probably would have worked just fine if they’d had it all along, or if they could have persuaded the rest of Europe to follow suit, but the world was too internationalized by that point, and they couldn’t afford to be running on a different schedule from everyone else. (It didn’t help that they lengthened the week, but didn’t lengthen the weekend — nine consecutive days of work had laborers going FUCK THIS NOISE.)

Sarah Monette’s Doctrine of Labyrinths does something similar, in that the city of Melusine has two different, somewhat competing systems of timekeeping in effect. There’s the shiny new one of months and weeks and years, used by rich educated people who have learned the new system because they’d look like a total rube if they didn’t, and then there’s the older, considerably more confusing mess of septads and decads and indictions, that the lower classes use because they don’t have any real motivation to change. Why should they? They know how it works.

I’ve heard readers complain about it, because there is no handy appendix in the back that tells you how long an indiction is, but I quite enjoyed it. Context usually indicates how long a time frame they’re talking about, and it’s a cool piece of worldbuilding. Not only does it contribute to the impression that this is a world with a rich, complicated history, but in dialogue and narration it also functions as an immediate class marker.


More scientific than trying to read entrails, anyway.

And to be fair, the moon revolves around the earth and everyone can see the effect it has on the tides. Stands to reason that all the other twinkly lights in the sky would also have some effect on life on earth, shouldn’t it? Astrology was a science in that its effects were not random, or resulting from the whims of a god — they were thought to be both regular and based on evidence drawn from nature.

(Johannes Keppler made his living as an astrologer sometimes, much to his chagrin, because a degree in math wasn’t all that lucrative otherwise. He is reported to have said that it was better than begging in the streets.)

Daniel Boorstin talks about how astrology dictated the structure of court life in imperial China, for example, how it was the empress and not a lesser concubine who got her conjugal visits with the emperor on nights when the stars were in alignment for making sons or whatever. Take that with a grain of salt, because Boorstin is a western-civ guy with a eurocentric bias a mile wide and a tendency not to notice when he’s talking out of his ass about Asia, but it does open up some very interesting possibilities for fiction. What if succession were determined not by primogeniture, but by which child was born under the most auspicious combination of signs? That may never have actually happened, but it would make a fascinating premise to explore in fantasy.

Case Study: Point of Hopes

Written by Melissa Scott and Lisa Barnett, Point of Hopes and its sequels are set in an Elizabethan-flavored fantasy world, with the significant twist that horoscopes are a really big deal. They’re determined by the time of one’s birth, and the more precisely you know your time of birth, the more accurately your horoscope can be figured. (Obviously rich people have the means to measure that with precision, while poor people likely have to guess it to the closest quarter hour.) It’s believed to influence and/or predict every aspect of a person’s life, to the point where a policeman investigating a series of kidnappings is trying to find out when one of the victims was born, in the hopes that her horoscope might offer some clues about her abduction.

Moreover, I liked that this belief was never proven true or false by authorial fiat. It stays plausible enough to have been a belief system that could have endured, as astrology did and still does, but doesn’t get legitimized as definitively real either, the magic usually does in fantasy.


(We’re coming up on the end now, I promise.)

The first thing to keep in mind is that for most of human history there hasn’t been a need for precise timekeeping. Time is only meaningful because we all agree that it is, so really, you only have to be as precise as your peers.

If everyone’s gauging time by the position of the sun, then “near sunrise” or “near noon” or “sometime before noon” works just fine. (Boorstin: “Since no one in Rome could know the exact hour, promptness was an uncertain, and uncelebrated, virtue.”) If you’ve got a town crier or a village clocktower announcing the hour, then your people might demand a bit more punctuality. Or maybe everyone who’s anyone carries a pocketwatch (or tucks an inro watch into their sash).

But even the concept of fixed time is a surprisingly modern invention. Before mechanical clocks, there were two general approaches people could take to measuring time: sundials and sand/water clocks. Only problem is, they’re measuring entirely different things.

Sundials measure twelve hours between sunrise and sunset. Twelve hours. Middle of summer, middle of winter, sundial don’t give a fuck. Every day is still going to have twelve hours, and an hour is going to be 1/12 of the daylight, which means that means an “hour” in summer is considerably longer than an “hour” in winter, and that is… not always so useful. As Boorstin puts it, the sundial is an elastic yardstick.

There are other obvious drawbacks to using sundials — they don’t tell you anything about time passing at night, and they don’t work on overcast days. A sundial has to be precisely calibrated for the latitude it’s being used at, which makes it less useful on a boat or for people who are going to be traveling. Hence, even in the Roman empire, when they had sundials galore, the day was only formally divided into AM and PM, and the only o’clock they bothered hiring a crier to holler was noon.

Water clocks (and later sand clocks) are not elastic, but they come with their own set of issues. There are two types of water clocks: ones that measure the inflow (in which case you need a source of water to feed into a graduated container) and ones that measure the outflow (in which case you need to account for the fact that the flow of the water will slow down as the amount decreases, since there will be less pressure.) In both of them, you need to make sure that the outflow spigot isn’t going to erode larger (and thus start flowing faster) with all the water that passes through it. In cold climates, the viscosity of water can change and mess up your careful calibration, or it might freeze altogether. In hot climates, water will evaporate off in an open system, and turn into steam and condensation in a closed one.

Even after the hourglass was invented, the basic problem remained the same: that these clocks measured a fixed length of time, but one that only existed in relation to… when you started the clock. It wasn’t synchronized to anyone else’s clocks, and so it wasn’t able to coordinate the rhythms that people lived by.

They were also constrained by the physical fact that in order to measure longer periods of time, they had to be able to hold commensurately more water/sand. A 24-hour water clock was a public works project; there is no such thing as a 24-hour hourglass. Most of them were considerably shorter, used for cooking, measuring church sermons and university lectures, on ships (there was a clever way to use them to gauge speed), by craftsmen to measure their working hours, and in courts to make sure that opposing lawyers got equal talking time.

(There’s a story about a lawyer who was particularly tiresome and also frequently drinking from a pitcher of water he kept nearby, leading one Famous Roman Wit to be like, “GAWD, why don’t you do us all a favor and drink from the clock instead?”)

In any case, bringing the two systems together — making a clock that was universal and grounded in the cycles of daylight, but that also measured off hours in fixed increments — required the precision of machines, and that didn’t happen in the west until the 14th century. It was in 1330 that the hour became 1/24 of a day. And thus, if you’re writing a fantasy world that hasn’t invented gears yet, think twice before tossing off a reference to hours.

Case Study: Jin

Jin is a Japanese drama about a modern-day neurosurgeon who falls down some stairs and wakes up in the Edo period. It’s better than it sounds, I swear.

There are a lot of things that a time-traveler visiting the unwashed past knows to expect (and let no one accuse Jin of avoiding those cliches), but they also do a good job of bringing your attention to the things you might not have expected — like how people figured time differently.

In the scene where Jin realizes that Holy shit, I am actualfax SOMEWHERE IN THE PAST, there are people walking around with SWORDS and KILLING EACH OTHER WITH THEM and unironically using ใงใ”ใ–ใ‚‹, what the screaming flying fuck–, the world’s coolest heterosexual love interest happens to be standing nearby, so he turns on her all manic-eyed and asks…

Jin: “WHAT YEAR IS IT??” D: D:
Saki: “Bunkyu 2.” ^_^ [cuz she rolls with his crazy like a champ]

Which doesn’t mean a thing to him.

Jin: …. o_O !? “Is this… the Edo period?” [1600-1868]
Saki: “Uhm… this is Edo.” [Edo = old name for Tokyo]

He starts to ask which shogun is in power, then realizes his command of history is shitty enough that it probably wouldn’t help.

Jin: !! “Have the black ships already come?” [Admiral Perry’s arrival in Japan]
Saki: “Yup! That was like ten years ago.”


Nor does it end there, because later he’s on the verge of a time-critical operation and realizes that he’s missing something vitally important…

Saki: “I can go back to the house and get it! It will only take one koku.”
Jin: “Bwuh? How long is a koku??”
Saki: “A koku is… a koku? What?”
Jin: “Uhhhhh what percentage of a day is it?”
Saki: “…….What?”

It’s not that she’s stupid — imagine if you were asked to explain our system:

Crazy person: “How long is an hour??”
You: “Uhm… 60 minutes?”
Crazy person: “…How long is a minute??”
You: “60… seconds?”
Crazy person: “How long is a second?!”
You: “SHORT!”

One koku, by the way, is about 2 hours — which I suspect ties into the zodiac-derived clock mentioned in Hojoki, above. A koku is two hours, so 12 koku in a day, twelve signs in the Chinese zodiac…

…and the events described in Hojoki took place in 1177, meaning that Japan (and presumably China as well) had fixed hours before the west, before machines, and Boorstin doesn’t know what he’s talking about.

Sonovabitch. This call for more research.


[After classical Japanese one day…]

Me: “Hey Professor, remember that book you mentioned in passing that one time and recommended for people who were interested in the history of time-keeping?”
Professor: “Yup.”
Me: “Well I read it, and Boorstin says that the fixed hour wasn’t possible until the 14th century with the invention of machines, but Kamo no Chomei’s reference to the ‘Hour of the Dog’ implies that the Japanese had fixed hours as early as 1177.”
Professor: “Yup.”
Me: “I tried looking it up on wikipedia to see when [the zodiac clock] was invented, but the English wiki doesn’t have anything about it, and the Japanese wiki just says that it was the system in use ‘until the kindai era.’ [1868]”
Professor: “Yup.”
Me: “How????”
Professor: “We’ll talk about it after the midterm.”

NoooOOOoooo, I want to talk about it now~~!

…or I suppose I could study for the midterm that’s happening in an hour.

8 thoughts on “A Brief (Social) History of Time

  1. I’ll certainly do at least a short update when I solve that mystery. I think the answer is going to be public-works-project water clock + bells/town crier, but I’ll let you know for sure. :D

  2. I grew up with the ridiculousness that is the Jewish lunar-solar calendar, so all those examples seem so tame and straight-forward. I remember hearing the real push to consolidate time from one town to the next was the invention of railroads. No, we need to know if the train is arriving at our noon or your noon, because we only have ten minutes to load our produce on it.

    I once read a book set in space that counted in metric units of seconds. On one hand, it was extremely sensible for the society. On the other hand, it took me to midway through the book to stop checking the appendix every two pages to tell if they were talking about a couple days or a couple decades whenever time was mentioned.

  3. HAH, yes, good points all — in fact the reason I didn’t include the Jewish lunar-solar calendar is because I didn’t understand Boorstin’s explanation of it. Methinks he might not have understood it either. >_>

    And you make an excellent point about railroads — that even though they may have invented the fixed hour in 1330, but it didn’t actually ~need~ to be fixed until the 1800s. I don’t suppose you remember where you read that?

  4. This post was fantastic! Also, I hope the midterm went well.

    Seems like the best way to handle it would have been to use dawn/noon/dusk until your society could have timekeepers to manage a water or sand clock. The clock could measure some fixed amount of time between two and ten percent of a day, and every time it ran out, they could reset it, increment an hour counter such as a clock tower, and ring a bell.

    I think we should all just write dates and times as something like “2013-302.661,111″. Dump the weeks, months, hours, minutes, and seconds, and just have year, day, milliday, and microday. We can just declare that the new year starts at the first midnight after one of the solstices, perhaps the northern solstice since that’s traditional, and so some years will have 365 days and others 366. No doubt we’d still use five, ten, and thirty day periods for various things, but we can just call them that. Might only work in a culture of mildly autistic mathematicians, though.

    Of course, the hours minutes and seconds come from ancient Babylonian mathematician-priest-astronomer-scribe-scholars who probably were mildly autistic, and were obsessed with numbers like 6 and 12 and 360, which is why we also have 360 degrees in a circle, which makes me feel better about ditching it for a metric one that matches our base ten system for writing all other numbers.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>