Heraldry is a peculiar mix of localized and universal.

By “localized,” I mean that it’s very specifically a medieval-and-later European phenomenon. The idea of individuals or groups having emblems is vastly older and more widespread, but that isn’t heraldry per se; it lacks the hereditary element that turns idiosyncratic choices into an organized system. In Europe, that system started forming during the High Middle Ages, around the twelfth century. By the middle of the fourteenth century you start having heraldic authorities responsible for recording and enforcing unique designs and color schemes, so that you can truly identify a member of a particular family by seeing their coat of arms — whether on the battlefield or off.

To the best of my knowledge, no other place in the world has quite this same practice. Japan comes close; mon or kamon (“family mon”) developed in the Heian period as a way of identifying members of the nobility so their order of precedence would not be in doubt. (It’s extremely useful to be able to answer that question at a glance! Heralds in Europe had similar responsibility for memorizing coats of arms and knowing who outranked whom.) In later centuries, certain mon like the imperial chrysanthemum were restricted, while others saw multiple uses by different groups. But although mon are hereditary — and, like heraldic arms, can be assigned to organizations as well as families — color is irrelevant as a distinguishing factor. And although mon can be modified to indicate a cadet branch of a family, there’s nothing equivalent to European heraldry’s system of quartering, where multiple emblems can be combined into one.

Tamgas on the Eurasian steppe are the other noteworthy candidate, as these are again a hereditary emblem of a family, clan, or tribe. Unlike Japanese mon and most of the charges (images) of European heraldry, tamgas are highly abstract, and their original purpose — still in force today — was for branding livestock. They’ve seen use outside that context, though, e.g. on funerary monuments, thereby expanding and strengthening the sense that these images represent the lineage more broadly.

The full system of European heraldry is ridiculously complex, its difficulty compounded by the fact that half its terminology is taken from medieval French. I’m not going to try and cover it all here (that’s a job for a specialized book), but I do want to note that the complexities of it very much developed over time. In fact, a lot of it dates to the early modern era and later, when coats of arms were no longer nearly as important for identifying men on the battlefield or in a tournament; instead they had become a decorative art, a little game played by the upper classes of society (gentlemen and nobility) and powerful organizations like universities and guilds.

In this game, the range of permissible emblems and how you deploy them expands enormously. Early heraldic arms went for a small number of impressive signifiers, like dragons, lions, and crosses; in later use you find mice, fish, and the tools of different trades. New colors came into use. Quarterings started to get out of hand; the arms of Charles V, Holy Roman Emperor, consisted of no less than twenty distinct components, representing all the places he ruled — some of them more than once, because of how he inherited them! (The most ridiculous example I know of cranks that up to three hundred twenty-three quarterings.) Furthermore, the emblems acquired add-ons like supporters, helmets, mottos, and crests, all of which were equally subject to the specific rules for heraldry.

But let’s loop back to that color thing for a moment, because this is where heraldry unexpectedly taps into something universal.

Do me a favor and take out your phone. Look at the icons for the apps. Or while you’re going through your day, look at the logos for corporations, the signs along the road. Count how many of them consist of either white or yellow on a colored background, or some color on a white or yellow background. This is a fundamental rule of heraldry in action, and it persists all these centuries later for good reason.

Heraldic tradition dictates how tinctures are organized and juxtaposed. For our purposes, we can lay aside the furs (specific background patterns); we’re concerned only with the metals — gold, silver — and the colours — blue, red, purple, black, green. (Heraldic history also includes a mulberry color between red and purple and an orange-to-brown color, but they were not commonly used, and later folklore decided those were “stains” that represented a dishonorable act.) According to the rule, you can juxtapose a metal with a color or a color with a metal, but not a metal on a metal or a color on a color. In other words, you can have white or yellow (representing silver or gold) against some other shade, but not white and yellow together, or red and blue, or green and black, and so forth.

More than just arbitrary aesthetic taste underlies this rule. By following it, you create a high-contrast design that is easily “read” even at a distance or in poor light. With modern pigments and dyes, we do have the capacity to make a green bright enough to stand out against black, or a red vivid enough to contrast with a pale, desaturated blue, but those rely on a command of coloration not easily attained when working with historical materials — especially when you consider the propensity of dyes to fade! If you want to be sure someone can make out your emblem at a glance, whether it’s on a battlefield or driving seventy miles an hour down a highway, following the medieval rule for tinctures is the safe way to go.

So I roll my eyes a little whenever I read a novel where the author, clearly in pursuit of badass vibes, describes the villain’s heraldry as being red on black. Sure, it sounds cool . . . but odds are high that somebody trying to make out the specifics at anything past close range just sees a blob of something red. Which I guess is fine if nobody else is running around with a red-on-black banner, such that the colors alone are sufficient, but still: nobody’s going to appreciate the artistic effort that went into your skull-and-snake design, because they can’t really see it.

Putting full-blown heraldry into a book is automatically going to make the setting read as European, which means it won’t suit every story. But as the examples of Japan and the Eurasian steppe show, there’s room for different systems of hereditary emblems, even if they aren’t as complexly elaborated as heraldry became in later centuries. On the other hand, the latter offers all kinds of potential for narrative fodder, whether that’s making a reality out of the “stain” notion or somebody starting a massive diplomatic incident because they confused one coat of arms with another that’s very similar!