1) Size matters. It’s up to you to decide how big your empire is going to be. Sometimes, as with alternative history, other forces make the decision for you; if you’re writing a Roman empire that never broke up, or a Spanish empire that maintained power into the 1800’s, then the boundaries are set in a way they aren’t with a created one. Other times, if the author’s drawn the map first, seas, impassable mountains, deserts, rivers, and straits will act to limit the empire in ways that they won’t on vast, unbroken continents.
Either way, the sheer extent of land presents a number of problems that don’t occur in one self-contained country which the monarch can ride across in three days. Some will be communication (point 2), travel (point 3), and class systems (point 4). But quite apart from all that, the presence of several different provinces/countries/lands/realms/take your pick of the name in the empire means that the acts of each individual part will have to influence each other individual part. And just because the capital city can throw its weight around doesn’t mean that the country outside the capital city won’t push back.
This is one thing I’m really sick to death of seeing in fictional empires: the author treating them just like kingdoms or, excuse me while I vomit, villages, where all the emperor has to do is snap his fingers and everyone jumps to obey and everything he wants is accomplished at once and the emperor is the most important person and truest ruler in the fantasy world. It’s not going to be like that. The more people the empire absorbs, the more chance that you’ll get shifting politics. These lands are bound to each other and working within the same political system and system of laws; they can’t just ignore each other. At the same time, the conquered lands may well retain old memories and wounds that they wouldn’t if they were all part of the same country and culture (point 4 again), and be pulling against the leadership of the land that conquered them. A king might, just might, be able to be on top of everything in a kingdom he could ride across in three days. There is no way that an emperor would be single and sole ruler in reality of an empire where travel time is measured in several months, no matter what it said in name.
Please stop acting as if the imperial family is the only group that matters in your empire, and their actions will control its fate. It really, really isn’t, and they really, really won’t. There are multiple other factors weighing in, the more of them the more land you add.
2) “Let me just consult the emperor, and I should have an answer for you in seven months.” This is in a way a subset of point 1, but then so are all the others.
It’s going to take time to communicate between the farthest outposts of the empire and the imperial city, or between the viceroyalty and the farthest outpost, or, for that matter, between countries that are at different ends of the same continent. Some of these are sheer travel problems, which I’ll address under point 3. But other than that, there’s the fact that:
-A lot of fantasy empires don’t have fast or reliable communication networks, yet authors set up plots that require characters to act on knowledge of events occurring near-simultaneously with their own actions. This makes for really confusing chronology, really sloppy writing, or the necessity for clever hand-waving, particularly with magic. It would be better just to acknowledge the problem and already have done the world-building or plotting necessary to counteract it.
-Messenger birds are the usual fallback. Yet even birds are mortal, and they’ll die, veer off-course by chance, get eaten by other birds, get shot by the enemy, drown when crossing oceans, and just wander away. Why people send only one bird with the all-important message is beyond me. Sheer law of averages would dictate that a whole bunch of birds with the all-important message would have a better chance of making it through. And don’t give me that guff about people finding the birds and that being disastrous; that’s what ciphers are for.
-An empire with several different conquered cultures in it, particularly cultures that were across oceans, is going to have, guess what, several different languages in it. If the locals aren’t encouraged to learn to read and write—and their rulers might have decided that’s too dangerous—then communications will go through imperial citizens and interpreters alone. They’re probably far-flung from each other, since you’re not going to get a whole bunch of people to agree to live in remote outpost number 10 without the luxuries of home. And if they’re politically opposed to each other and intriguing, what reason will they have to speed judgment on, say, a criminal case whose resolution would help a rival? Not a whole hell of a lot.
-Empires mean bureaucracy. That doesn’t make for fast communication.
The bigger the empire and the lower the tech level, the longer it’s going to friggin’ take. And we haven’t touched travel yet.
3) Oceans are fun until you’re actually trying to cross them. Haven’t you found that in the past?
This is the other major side effect of having a huge empire. Varied terrain means varied weather, death traps, means of crossing (which come with their own hazards), and unique time-wasting obstacles. It’s perfectly possible that by the time a message, a detachment of troops, or a new governor reaches that remote outpost, the crisis will have settled itself, one way or another. And that’s not counting the time that the first message about the crisis takes to get to the empire’s capital, or how long it would take to reach someone who’s inclined to do something about it, or how long the preparations for travel, after the making of the initial decision, would take. “No-nonsense efficiency” isn’t going to be a guiding principle of necessity. You’ll have to show that it is, and give people reasons for choosing to hurry.
First of all, oceans. The crossing from England to the American colonies could take as long as three months. And it was an uncomfortable three months, in ships that wallowed and stank, on which there was no privacy and almost no space, where many passengers drowned thanks to storms or even ordinary rough seas. Little variety in food, crowds that encouraged the wildfire spread of disease, and the sheer discomfort and boredom of ocean travel all militated against someone going to the colonies unless they had pressing reasons (or no choice, as was the case with transported convicts). Many people originally sailed with the thought of coming back to England when they’d made enough money to do so. If you have an ocean-spanning empire, don’t assume that people will be just lining up to get to the colonies or that every voyage is smooth sailing. Do some research and give your people good motivations for abandoning the mother country.
Second, journeys across continents. There was a reason that the Roman empire was so hot on roads. Moving thousands of foot soldiers, often heavily laden with armor and weapons, or horses likewise laden, across dirt trails is just not on. Here comes the rain to turn the dirt to mud and get the wagons and horses stuck, whee. Here come the highwaymen who know the land better than the foreign troops and know that imperial soldiers don’t have the time to waste pursuing every gadfly who bites them. Here come the local resistance troops who not only know the land better but might even have had imperial training if they took turns serving in the empire’s levies, and have the burning grudges from the conquering of their countries to drive them on. Add in all the “ordinary” hazards of traveling parties that a lot of fantasy authors go after in loving detail, and you can give up this miraculous picture of the empire’s troops marching for sixty miles every day without help.
Third, perilous terrain different from their home ground. You might have desert troops who are expertly trained in fighting without water and without shade and in the midst of great extremes of heat and cold. It doesn’t mean that you can plop people from the desert empire into the middle of the jungle and expect them to do everything right the first time. To think about the very simplest matter, in deserts you can often see for quite a long way and, assuming you have a mount who can make it across sand, move easily. Jungles are closed-in environments, and the troops will probably have to hack their way through vines with a machete to move a few feet. It would be better for the empire to raise and train local levies—except that they may have burning grudges from that little bit of conquering the empire did fifty years back.
Do think about travel. If nothing else, this would make a great area for the mages of the empire to concentrate their research and their spells on.
4) “We’re all one big happy society!”…not. A country may have a strong, cohesive identity, based on local language, customs, magic, bloodlines, religion, sharing the same place, and any number of other things. It’s a lot harder to export that cohesive identity to other parts of the world and convince people that they want to be part of it without force. (And I’m counting economic force in here as a weapon. Your empire may not go out and conquer other countries militarily. Doesn’t matter. If they dominate them with money and trade, and could devastate them by a simple alteration of mercantile policies, it’s still force).
There’s problems, potential cracks and conflicts—and therefore potential stories—everywhere in an empire. Let’s start in the center and move outward, shall we? Say the empire has expanded rapidly. People in the capital city or kingdom may be stunned, a little proud, and a little frightened. They’re going to be anxiously aware of new responsibilities and burdens, whether they conceive of it as a religious mission, a moral charge to “take care” of “less civilized” people, or the natural result of their being naturally superior. If there are other powerful nations or empires in the world, they’ve just taken their place among them, and they’ll be aware of those nations or empires watching them more carefully. They’ll like the new goods pouring in, too, and pretty soon will become convinced that they can’t live without, say, tea or the new spice or that illicit drug that makes you feel like you’re flying every time you take it. They may even have conquered those countries specifically to get at those items.
It’s a fine tightrope to walk. The empire could make many “good” decisions, and still end up binding themselves tighter and tighter into that political web that will make it harder to move as time goes by. If they conquer a new island off the coast of the enemy nation, they may get plenty of fine silk from the island and have a new place to send the unwanted of their own society, but they’ll also have a new frontier to fight on, a new group of people to homogenize and assimilate if possible, and a new rift between themselves and the enemy nation.
Also, their own culture may be such that they make unwise decisions in countries so different from their own. The Spanish empire took off the way it did partially because the conquistadors were the descendants of a culture that for eight hundred years had trained fighting men to take Spain back from the Moors. They were restless, fierce, impatient, and often believed utterly in the rightness of their cause, and once the Moors were gone, they wanted new lands and enemies to conquer. They found them in the Aztecs, Incas, and other nations of the New World.
If they’re an old empire, steadily and slowly expanding, they may be used to the charges and changes of power, but that doesn’t mean it’ll be easy. That very laid-back attitude could cause the empire problems if it steps into a brand-new territory with challenges severely unlike any they’ve faced before. Say the empire’s gotten used to judging opponents on their military technology alone. They venture into a country that’s poorly equipped militarily, and take it over—in the summer. Then comes the winter that they don’t know how to face, and slaughters imperial troops by the thousands. Just because an empire has ruled many countries for centuries is no guarantee that things will go smoothly this time.
Then consider what it’s going to be like in the territories/colonies/outposts. Imperial officials will tend to see themselves as superior, since if people are in power, they tend to make up justifications for having it and keeping it. The natives, if conquered in the first place, are not going to register on their radar as worthy of respect. Oh, they may be good enough to keep as servants, to sell as slaves, to fuck—and produce mixed-breed children who will probably be legislated under a complicated caste system—and to shoot idly at for target practice, but put them in governance over their own people? Not likely, until they’ve been ‘civilized’ and groomed and taught the language and taught the laws, and even then, can you trust them as much as someone reared in the empire? I didn’t think so.
The natives are simultaneously going to resent this and, as generations go by and the imperial conditioning sinks in, come to half-believe it. They may see themselves as citizens of two worlds, particularly if they’re of mixed races, species, or classes by ancestry, and not know which one they belong to, or if they should create a middle-road world of their own. There will be groups preaching assimilation into the empire in a hope for full acceptance, groups preaching bloody revolution in the hope of going back to what was before, and people of every stripe in between. And if you’ve got several castes in there, such as imported slaves, people whose ancestors were imperial citizens but who have lived all their lives in the colonies, people who are immigrants or traders from other countries, different species/races, and people with mixed ancestry of various kinds, you can imagine the kind of complicated, layer-on-layer situation that piles up.
Then there’s relationships between colonies. Are they rivals? They often will be, especially if seasonal changes and changes in the political and economic winds cause the mother country to favor now one colony, now another. They may be friends at some times, but still distrust each other; ingrained prejudices, especially ones imported from the mother country, will help take care of that. Divergent linguistic and cultural patterns will make them suspicious of each other. If one colony revolts and is bloodily suppressed, the empire might be irritated enough to bring down consequences on everyone’s heads, after which the others will lay low and blame the original revolutionaries, who will blame them for not having enough courage. There’s no end to the permutations you can get into here.
And then there are the countries watching outside, waiting. They may prey on the empire if possible, the way that English privateers did on Spanish treasure ships. They may adopt an opposite political stance, like abolition if the empire is slavery-run, just for the sake of separating themselves from their stronger enemy. They may work with it, accept a discarded colony in exchange for help during a war, and/or try to build themselves up as rivals. (Often, in our own world’s history, both were happening at the same time). They may bide their time and strike unexpectedly. Sure, there’s full-out war, but there are all sorts of alternatives to it as well.
Why would you want to write the big, happy, shiny empires where every single person is loyal to the emperor and the empire is always right when it conquers a new country? The reverse is much more interesting.
Damn it, there will have to be another half of this rant, as this got much longer than anticipated. Well, hey. It’s a fertile subject, and I’d like to see a lot more done with it than currently is.