How transportation technologies shaped empires

on my machine this pdf is barely readable, here's a copy https://pure.iiasa.ac.at/id/eprint/4071/1/RR-95-04.pdf

(hope it's not a problem for the author)

ps: as a sidenote, I remember someone saying that the invention of fridges is a factor in the evolution of cities/transporation too. Never found solid work on this but it makes sense, you keep things closer if you can't conserve food.

Very entertaining read

But for future interplanetary colonization, the rule would become one light month. Not very far. But imagine any form of communication taking years to bounce back and forth. That could not be centrally governed. It might not just be travel time, but it probably does correlate.

The logic is fine, it's just massively overstated with the clickbait headline, and travel time in a region is an endogenous factor which depends on where the boundaries of the empire are drawn, because empires build roads, chop down forests, drain swamps and make rivers navigable.

As the article acknowledges, travel times within the Roman Empire tended to be less than a month. But they conquered land regions (where possible) before they built the roads that let them supply them that fast. Certainly there's nothing about lowland Germany that should make it more difficult to reach than Hadrian's Wall, but they effectively subdued the British tribes and built roads all over that particular faraway island, and didn't have as much success against the Germanic tribes who inhabited desirable land closer to their capital that could have been reached in a shorter time with a nice lowland road from Gaul, if they'd ever been able to build it.

It's really about trading routes. Today different regions of the world specialize in different industries. You get competition between people vying in the same industry and between trading partners. Communication really doesn't help when it comes to corporate/national power struggles. This is also why so many 'brother' countries tend to fight; Ukraine and Russia, Yeman and Saudi Arabia, Eritrea and Ethiopia.

The "logic" or lack thereof is in trying to find a universal "hidden rule" in large-scale human behavior across literally all of recorded history. This is pure physics envy, and it never ends well.

> The logic seems sound to me

It seems less than unsound. It's barely a just-so story.

> empires that span the globe are much more feasible today

A lot of people would argue that ~half the world is part of the US empire today...

In that the US has power to strongly influence/make decisions in about half the world, extradite people from about half the world, and enforce IP/anti drug/monetary controls in about half the world.

And by some definitions, it might be 80% of the world.

Barbarism is certainly a factor in the Roman expansion into Germania, but if you look at how the Romans were able to colonize Gaul completely. I think originally they thought they could follow the same playbook into both Germania and Britain. Britain was never full pacified and required a large occupation force to keep the province under control. After the defeat of Varus during the reign of Augustus, I think Roman leadership looked at the area using a cost/benefit analysis and decided it wasn't worth the amount of money that would be needed to fully pacifiy the region. The Romans should have pulled out of Britain after Claudius, the invasion was a vanity project and had no real value as a province.

> Anyway... I think Rome's limiting factor in germania and the european frontier was barbarism. NW europeans didn't have civilization: states, monarchies, temples, senates, roads, nations. The germans didn't even know they were germans until Romans told them. Rome's empire was based on assuming political control over existing political institutions.

I think you could get a job writing excuses for Roman emperors ;)

The Romans might have assimilated some sophisticated civilizations like Greece and Carthage, but outposts like Britannia were nothing like that, and Romans built their own roads and cities and villas to extract wealth from the land and set up their own institutions everywhere they went. Germany had no shortage of potential as a source of agricultural produce and slaves, but what made it uneconomical compared with other fringe parts is the pesky Germans kept fighting back, and in particular wiped out the three remaining legions in Germania after eight others sent there to pacify it had been withdrawn to stave off rebellions elsewhere. (They lost a legion to Boudica in Britain too, but they'd built roads and cities there by that time and had a different emperor calling the shots).

you are all wrong people,

Roman legions were co posed of Roman citizens, they had to procure their own sword and shield, and could be called up to serve.

As the Roman empire grew, they captured many slaves and territory. Wealthy romans could buy up slaves and land. They accumulated large holsings farmed by slaves and could outcompete ordinary romans in agricultural production.

This was a problem because they were bacrupting the very same people who formed the legions. All the legionairs would recoeve for their military success, was increasing poverty.

This led to decreasing quality of troops and political instability

From what I can find: In 1858 – when the British Raj was established – it took about half a year since you had to go around cape the good hope. After the Suez canal opened in 1869 it took only ~2 months. In the following two decades expansion of the train network and faster steamboats further reduced it to about 2 weeks.

So it really depends a bit on which period you're talking about as there were lots of things going on during the period, but for a substantial part of the British Raj's existence you could get there in a month or less.

I expect the "law" is not as simple as "1 month travel time", but rather a calculation that factors in both travel time + communication time. For much of history these two value were mostly identical, but this changed with the adoption of the telegraph (and later, radio).

Let alone that the Portuguese were in Brazil, and the Spanish in the _Philippines_, for some 300 years

I didn't write the article so I don't care either way, but I think the British Empire was a thing totally on its own. Probably (probably, I'm not a historian) because its technology (both physical and organizational) was so much more superior to the lands they invaded that the normal "laws of empire physics" didn't apply.

In Australia (and NZ, and Canada, and the US, and probably in South Africa to a certain degree) their mode of operation seemed: reduce the locals to nothing (even worse than Spain), then build a fully Western-like society. Clean slate, mostly self-governed by white people who are not inclined to fight with Europe (with notable exceptions, obviously)

In India - although I don't doubt for a second they killed many many people - they seemed to operate more like the Golden Horde in Russia: as long as you pay the taxes (and occasionally provide more stuff when we run out), you can keep your culture and be governed by your local warlords, because it's just too tedious to kill all of you at once. The British did seem to have a bit more sway though, for example when they kicked off the partitioning, millions of people started moving. However, largely it seems like a brutal but mostly hands-off rule (based on mutual benefit with the local elite?)

What they did in Africa was something else, I've read books about insanely remote places like South Sudan or Zambia, and what were they doing there is hard for me to understand at all. But again, the gap in technology between the local people and them was so vast that they could do whatever they wanted without much coordination with the capital.

The Romans and other empires of the past were different because they didn't have such a huge technology gap. In case of Romans, you still fight it out with spears, swords and bare hands, and they tended to take over the lands completely, and impose their own gods, order and culture, which is much harder to do with a similar level of technology and does require coordination with the capital.

British Raj is a great argument for the article, started in 1858 and lasted less than a century, a blip in the historical context, as power projection was a recurring problem.

were they ruling it or plundering it for most of that time, and after they started ruling, how long did it last?

One could argue the British augmented that by creating better local institutions in the far away places.

Discontent seems (to me) implicit in foreign rule though, the degree just being a matter of with what and for how much the local population is being bought off.

Are there any examples where an empire doesn't treat it's outer reaches as second-class citizens and survives?

If you take Russian Empire/USSR for example, most of the territories which have been lost are much closer to Moscow (Ukraine, Poland, Finland, Belarus, Georgia etc.) than the territories still under Moscow control (Siberia), so at least in the Russia's case, it's not about transportation at all.

Sounds like the "No True Scotsman" defense. "Oh, that was just an outlier. The real parts of the empire were ..."

Russian saying: be further from higher ups, closer to the kitchen (подальше от начальства, поближе к кухне)

This medieval example sounds like an easy shortcut though.

At part of Europe, roads were always maintened. Maybe with more local that country-wide focus sometimes. The feudalism may not caused by road system efficiency. Good roads on a empire splitted by succession are still no match to fast manoeuvrable drakkar raiders.

Local power and defence is needed... leading to another important parameter. Size of empires is proportional to time of travel and relative defensive strength of the remote area.

You might find this series of posts interesting.

https://acoup.blog/2019/05/28/new-acquisitions-not-how-it-wa...

The third part in particular talks about geography and logistics of governance in Westeros.

Also the stability of the Kingdoms of Westeros is ridiculous given their ages. Supposedly they were divided into the Kingdoms of the North/Vale/Iron Islands/Reach/Rock/Stormlands/Dorne in the Age of Heroes - 10,000 years before the Targaryen conquest. 10,000 years is twice as long as all of recorded human history. In that time on earth, dozens of empires have risen and fallen. The center of civilization moved from the Middle East to Egypt to Greece to Rome to Byzantium & Arabia to western Europe to Britain to North America. Independent civilizations with equal claims to greatness sprung up elsewhere on the globe. Civilizations got conquered, technology advanced, genocides and plagues and famines happened, languages changed, and dynasties typically lasted a couple hundred years, if that.

Meanwhile, over in Westeros, the same 7 kingdoms have been ruled over the same geographic extent by the same 7 families at roughly the same level of technological development for 10,000 years. It took outsiders with dragons to conquer them. No explanation is given over how you could maintain what appear to be feudal structures over a 3000+ mile continent with bronze age technology.

Article is a little light on details with regards to why the author believes this effect exists. I have to imagine that their thinking is that application of force is limited to the distance you can travel one month instead of anything that would relate to the application of soft power (e.g. communication).

Supplying a ground based force follows more of a square-cube law. You need to feed your horses to transport your food to feed your soldiers. Going further means more food for the horses to carry the food for the horses to carry the food for the soldiers. There is an excellent post here that explains this far better than I ever could: https://maximumeffort.substack.com/p/the-tyranny-of-the-wago...

Any limitations on space based empires, while similar, are going to follow somewhat different rules depending on the tech involved. Unlike horses, once you launch you don't really have an opportunity to resupply a space based force going a long distance without inordinate energy expenditure. I'm not convinced force projection over a galaxy would be a problem for a civilization capable of travel at a significant fraction of the speed of light. Solving one problem (travel) necessarily solves the other (distribution of force).

I think the bigger question is more, why bother? What possible reason could a civilization have to go to war at that scale? Human civilization would need to change so much to get to that point that I'm not certain these are questions are explorable at our place in the timeline. We'd be like Romans dreaming about a better abacus.

This has been a recurring theme in sci-fi going back decades. Le Guin's Hainish Cycle is mostly this kind of universe, for example, even though it has FTL comms (but not travel).

Of course, none of this matters if you do have FTL travel, which the "space empires" kind usually does.

Communication obviously plays a big part but I think time to action is probably the better metric. You need to be able to act quicker than your opponent, and if you can't, you need to be able to absorb the damage they can inflict in the mean time whilst still having enough resources to inflict more damage than you sustained when you can eventually act.

> before the advent of instant communication.

But! Instant communication is not possible. :) This sounds like a nitpicking but this might become important if we spread out in space: We still have the light speed limit on communication.

Which of course means that our communication is practically instantaneous around all of earth. (at least when measured against human reaction times.) But if we would spread ourselves to let's say the Oort cloud you would see very serious lag in communication. Not just between Earth and the cloud, but between points on the Oort cloud.

Could the whole cloud ever be controlled by a single empire? Or would it break into a Voronoi diagram of "1 light month" large cells around points of interest?

Afghanistan was part of large empires like Kushans, Graeco-Bactrians, Achaemeniens, Mauryas, Mughals, etc for long periods. It was also a part of the Silk Route to India through Khyber pass and was the epicenter of Graeco-Buddhist art centers like Bamyan and Mes Aynak. It was not un-navigable.

The interior of Africa, too.

East Turkestan is arguably even more remote, yet China manages.

TIL that cataracts aren't necessarily waterfalls.

Why, I’d wager that, with modern Victorian transportation, a man could travel all the way around the world in less than eighty days. Meet me on the steps of the Reform club!

Phileas Fogg’s example Suggests that at the height of the ‘sun never sets’ era, nowhere should have been more than 40 days away from London. And with a significant chunk of that time stuck transiting the pacific, brings the majority of the world into the 30 day window for a single month.

"The regional governors now have direct control over their territories. Fear will keep the local systems in line."

Delegation of authority seems to partially help solve the problem.

I guess the distance is also proportional to the strenght of the remote part and the brutality of a vengeance from the capital.

England, Fance, Spain, Portugal keeping colonies for a while until they technologically matched and that enlightened europe would be less tolerant of a bloody revenge.

Russia, China still controlling their colonies because there is no local comparable strenght in those moutain/toundra/desert parts.

You can get around that by turning the empire into a federation which is the case in most sci-fi novels

Fortunately, while this study may exist, imperial ambitions know no bounds, so we'll colonize just fine. Sure, decades later, they may break away, but that's decades later's problem.

Plus, this analysis is implicitly in the context of a world where the regions have the ability to be self-sustaining on at least the basics of life, so breaking away is a viable option. If the "empire" is also "your supply of oxygen", breaking away will be a lot trickier. For a space colony or set of colonies to be able to break away, they first have to be truly 100% self-sufficient, and that's a tall bar for the forseeable future. They then have to be able to militarily match what the empire is willing to throw at them to retain them, and that's a very complicated analysis, made all the more complicated by not knowing what the exact technologies will be at the time.

(Plus, not all empires are complete buffoons. They at least begin being competently run. The empire will know that to break away the colonies must be self-sufficient, so they will take steps to ensure they won't be self-sufficient. And the colonies will take steps to become secretly self-sufficient. Long before open rebellions occur, there will have been a clandestine war of self-sufficiency.)

Or increase them? Presumably some portion of humanity might be motivated by trying to get away from existing empires (maybe creating new ones, maybe not), rather than expanding existing empires.

Why? Settling new places doesn’t have to mean expanding the existing polity: the settlements can be self-governing. See the Polynesian expansion through the Pacific, which to me is a closer (and more hopeful) analogy to space colonization than anything nineteenth-century Europeans or ancient empires did.

And so long as we’re just thinking of this solar system, there’s also the question of whether what’s important is transit time or communication time. Historically those were identical; now very much not.

Those colonies would simply become independent in a relatively short period of time.

Unless the settlers form a democratic and self-governing society, not an authoritarian empire

Depends on the velocity. 1 light month is pretty big.

Only if they are self-sufficient with respect to the basics. It's hard to rebel when the other side can just cut off your food supply until you starve into compliance.

With better propulsion, trips to mars could be shorter. There are times where Mars is on the opposite side of the sun, and times when Earth and Mars are close.

Another relevant factor is self-sufficiency regarding basic needs. But yes, if/when a Mars colony becomes self-sufficient, secession probably isn’t far off.

You can travel to Mars in 5 minutes so I don’t think so. It’s clear even in todays world you don’t need “boots on the ground” to exert social or military influence.

That's a fascinating question. I guess the answer is both. Fast info gives you extra time since you don't suffer the latency to send the shock troops.

Not sure Venus is within 1 month travel time.

Granted this is with Apollo era technology... but we're still talking Saturn V

https://en.wikipedia.org/wiki/Manned_Venus_flyby

> The proposed mission would have used a Saturn V to send three astronauts on a flight past Venus, which would have lasted approximately one year.

> ...

> Phase C would be the actual manned flyby, using a Block IV CSM and an updated version of the Venus flyby S-IVB which would carry a large radio antenna for communication with Earth.

> ...

> The Phase C mission was planned for a launch in late October or early November 1973, when the velocity requirements to reach Venus and the duration of the resulting mission would be at their lowest. After a brief stay in Earth parking orbit to check out the spacecraft, the crew would have headed for Venus. ... After a successful S-IVB burn, the spacecraft would have passed approximately 3000 miles from the surface of Venus about four months later.

Of note https://trajbrowser.arc.nasa.gov/traj_browser.php is fun to play with. - Custom list (Venus), one way rendezvous, minimize duration, all trajectories.

The shortest one is an 80 day one "burn straight there" approach.

I'm not sure that NASA has that updated for more recent years (its a search - not a compute) - still gives you an idea of what is doable and the inner solar system opportunities are fairly consistent (compared to the Grand Tour https://en.wikipedia.org/wiki/Grand_Tour_program which is once every 175 years). See also https://en.wikipedia.org/wiki/Interplanetary_Transport_Netwo... and if that sounds like fun, then High Frontier board game might be up your alley ( current edition https://iongamedesign.com/products/high-frontier-4-all https://boardgamegeek.com/boardgame/281655/high-frontier-4-a... ).

The article wasn’t on trade exactly, but makes the argument that travel time determines empire limits (geographically or temporally). If this is true, trade probably played a significant role in the effectiveness of empires in maintaining control.

That is, I don’t think your comment is a counterargument, unless I’m missing something.

You are right of course but I think Canada is a pretty unique case. Canada exists in huge part because of the american revolution. British-american loyalists have basically founded upper Canada, which is now Ontario, so it makes sense that they were particularly close to the throne and the British homeland and government. French-canada was also just recently conquered and placated by the Quebec Act, but still tried a couple of uprisings during the Patriot wars of 1837-38.

I don't think Canada would've stayed british without the loyalist escaping here, since they made it an inherent part of their identity to not revolt against the british as opposed to the americans they left behind. But agreed, there are too many exceptions in general to the article's point.

I would say that Canada managed to stay loyal to the crown because for two major reasons. The first being the founding "myth" of Canada being the British loyalist colonists of the US migrating as a result of the US' revolution. Them fleeing north to a major seat of political power likely had a strengthening effect on being a willing subject to the crown than most colonies.

Secondly, Canada is something of an imperial power unto itself. There are countless stories of armies marching under the crown violently clashing with nations that existed on the continent prior to European colonization. Likewise, even other European descended colonist as well as the Métis were subjugated by British rule as the Anglophone powers expanded across the continent (e.g. Queen Anne's War, Red River Rebellion, and Fenian raids). Gaining the ability to exploit the natural resources that these other nations and colonies held.

The crown was a convenient way to gain both legitimacy from the British loyalists who settled in Canadian territory and a reliable trading partner to receive resources from in the British Canadian bids for expansion. Compared to the US, who used democratic rule to gain its own legitimacy; and who's natural resources were abundant enough to be a valuable trading partner.

>we forget about the existence of the control case: Canada.

Is it though? England did lose Canada to home-rule. In fact, I contend that a major reason why a newly independent (but also broke and fledgling) Canada was not annexed by the US was mainly because of the American preoccupation with civil war and Reconstruction, and the diplomatic efforts of John A. Macdonald.

There is quite a difference between conquering (and thereby assimilating) versus killing almost all natives and then populating the place with your own settlers..

Or Spain and South America?

And even more so, re: distance, Australia.

Russia to Far East?

"Drunk the cool aid..." In the UK case I've heard the idea that the Publc School system emerged for exactly this reason. ('Public' schools being the most elite schools in the UK).

A relatively small number of schools shaped a class of people who all thought in exactly the same way, so they would behave predictably even when far away and in a new context.

Public schools, are not coincidentally noted for a focus on 'playing by the rules' and 'fair play', as inculcated through sport. Not to mention never breaking your word. All handy traits if your goal is breeding administrators you can trust without supervision.

History of Empire, History of Travel Technology, and History of Communications Technology are huuuuge fields with tons of professionals working today. I'm a little concerned about huge claims being made about empire by a Stanford MBA and a community of people mostly experienced in software and tech.

The historians would love for you to read their books! AHA is literally happening right now! Go to bars in Philly and talk to them!

> The way the empires get around this problem is by putting people who have drunk the kool-aid in positions of power.

I always understood the aphorism as taking delegation of power into account — it's "one month of travel" not because of the needs of top-down command-and-control, but rather because delegated power that's more than a month away falls past some threshold of latency required to "keep them in hand."

The aphorism might make more sense flipped in perspective and inverted: as a magistrate/governor, if you see your colonists suffering under the tyranny of a remote power, you'd better be at least a month away from that power to be able to quietly rebel under the nose of that remote power. Otherwise a quiet rebellion will never work — any closer, and they'll be constantly watching/auditing you. At a closer distance, if you want to rebel, the only option is an active, bloody rebellion — and if that's unpalatable to you, then you'd better just not rebel!

Empires that expand beyond the 30 day travel limit tend to fizzle out and crumble.

Today, of course, we travel the whole planet roughly 30 times in that time frame. So it's not a limit on Earth anymore. But it was definitely a problem for all previous empires. The ones you listed prove the point. They all crumbled when they expanded too far.

The reason is kinda obvious: If it takes 30 days to travel, it takes 60 days to travel there and back. Which means there is, at minimum, a 60 day delay between the start of a rebellion or war and your ability to respond to it. That's assuming you were ready for the news the moment you got it. Good luck with that.

It's just one of many reasons why wars are won more by logistics than bullets.

So I think it raises two really interesting questions:

(1) Here on Earth, the elimination of this limit is pretty recent. Should we anticipate an empire that spans the globe truly taking over? (No need to sarcastically comment about America today.)

(2) How does this impact space travel? Based on current and foreseeable technology, there's no planet we can regularly reach in that amount of time, because at any given time, the other planet could be on the other side of the solar system. Can we really colonize new areas if we can't reach them faster than 30 days? Maybe we can. Communication is nearly instant (relatively speaking), and there are no enemy combatants to deal with. But they'll still be stuck on their own if any unforeseen emergencies arise. Those never happen, right? Would we most likely see the formation of a new nation on each planet we colonize?

It is for the Romans though, https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2609654 as for the others I'm a bit sceptical but haven't to knowlegde about them either

>centralized decision making

Which bodes poorly for increasing federal power in the US.

To be fair, Dutch control of Java was more on paper than it was in reality. Most governance was devolved to local Rajahs who paid tribute to the VOC. Actual guns on the ground control across Java and most of what became Indonesia didn't really happen until the late 19th century

Also, Goa's existence was because it was so marginal. The Mughals, Marathas, and various regional kingdoms didn't care enough about the Portuguese, and also it was de facto treated as a factory (a free trade zone) - just like Surat was for the English

> The Netherlands conquering Java in 1619? A lot more than a month.

For practical purposes this was more the VOC than the Netherlands. Similar situation with British India until they killed off the British East India Company; before that, well, you could call it an empire, but it was really more a separate country ruled by a _company_.

Goa is probably a better counterexample, granted.

sure but I imagine the argument here is that the grip on power of provinces so far away was considerably weak and likely to an extent devolved to the local agents of the crown. And likely as long as the ships with goods sailed limited questions were asked and limited checks occurred.

I imagine that those who worked on the colonial extents of the Empire were given the largest freedoms to be monstrous as long as it benefitted the crown. I would even argue that the cultural descendants of these agents are the same forces that encourage ideas such as Brexit; hoping to return to times of significantly less oversight from the home nation. As an example of this internal discord between territories of European empires and home states I think the abolition of slavery in the 19th century was a scenario where the electorate didn't align with these colonial interests to create an internal discord. Agents then shifted to an evil interpretation of contract law to replace slaves with indentured servants. I appreciate that this might not seem immediately irrelevant but I hope it might show how a discord between the competing interests of the society at "home" and the society "abroad" might slowly result in the "transport time" fractures this article discusses as the interests of the two populations diverge.

I'm not sure capturing and holding an island would constitute an empire.

The Macedonian and Mongolian Empires shattered into more manageable bits almost immediately.

For Victorian Britain: https://upload.wikimedia.org/wikipedia/commons/8/86/Isochron...

Alexander the Great and the Mongol empire are specifically addressed in the article. Maybe read before "entering the chat"?

Alexander the Great wouldn't count as his empire fractured upon his death almost immediately after his conquests

he addressed all those didn't he?

"Queen Victoria, Chinese Gordon is on line one. Shall I tell him to hold?"

Eventually collapsed.

Collapsed eventually.

Collapsed immediately upon his death.

It’s about 5000 AU.

That means an Earth based space empire could encompass the entire solar system, but the limit of its reach would only extend part way into the Oort Cloud. Beyond this would be a lawless frontier.

Since this is based on the speed of light, it could be the maximum size for any empire in the universe without the use of some kind of FTL technology.

Kind of a tangent, but uh, this is my personal favorite argument for why Bitcoin et. al. aren't needed (yet): the diameter of the Earth is small compared to the speed of light. Maybe when we colonize interstellar space we will need blockchain.

In essence, one star system. Planet orbits are generally much less than a light month, and distance between closest stars is generally much larger than a light month.

30x distance to Voyager

1/50th the distance to the nearest star (Proxima Centauri).

1 light year = ~0.3 parsecs

1 light month = ~0.025 parsecs