Suppose a group of time travelers from our present went to Ireland in the 17th century and gave the Catholic Irish assault weapons and training (as in The Guns of the South), to use against the English?

This would be during or after Oliver Cromwell's military activities there, so that the majority of Irish would probably be motivated to fight the English. And as in The Guns of the South, the time travelers are politically motivated to change history.

Also, if the Irish succeed in destroying all English power in Ireland, the time travelers will call it a day and go back to their (altered) present. (They don't want to give the historical Irish a permanent huge military advantage over everyone else, and if some of the Irish wind up going back to fighting each other, the travelers don't want them doing it with modern weapons.) So the historical Irish will soon run out of bullets, etc., that are compatible with assault weapons.

  • $\begingroup$ Are you asking about the military results only? $\endgroup$ – HDE 226868 Nov 27 '15 at 14:46
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    $\begingroup$ I'm voting to put this on hold as it's got too many possibilities. I often think this with time travel questions: The answer could be anything. If you can re-couch the question into terms of 'What would 17th century Irishmen do if...' terms then it would bring it back a bit. $\endgroup$ – Joe Bloggs Nov 27 '15 at 15:52
  • $\begingroup$ One big difference between The Guns of the South and The Guns of the Irish is that the Confederates, both as individuals and as an army, were thoroughly used to fighting with guns, just not such advanced guns. That wouldn't have been true of the Irish in 1649. $\endgroup$ – Lostinfrance Nov 27 '15 at 20:25
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    $\begingroup$ How much ammunition will they carry? The guns will just be impractical clubs once the bullets are spent. $\endgroup$ – Burki Dec 20 '16 at 14:16
  • $\begingroup$ @Burki The North was concerned that lever action rifles would consume so much ammo that it would collapse their logistics. An additional question would be how many guns are brought back? Enough to arm every soldier along with spares just in case? $\endgroup$ – Englishman Bob Feb 21 '18 at 17:08

I hope your guys can speak German.

The mistake your time travelers made was not accounting for ALL of the assault rifles and their ammo. Not long after they left, a small group went looking for vengeance and succeeded in assassinating Cromwell using the assault rifles.

With the strength and prestige of the protestants in shambles after the defeat in Ireland and losing their leader, Charles II returned earlier than in our own timeline, established freedom of religion and openly became a Catholic in order to further an alliance with Louis of France against the Dutch and Spanish. The Glorious Revolution in 1688 never happened and in the next century after some cross-marriage, the result was one united Roman Catholic Anglo-French kingdom. Ireland lived in relative peace during this time.

The protestants finally saw their chance when the French revolution broke out in Paris and attempted to spread the revolution to London. They were however defeated when the french Royals decided to abandon France and move their army to London, aided by an Irish army that was not keen on a Protestant revival. Scotland did successfully declare and keep its independence, aided by the Dutch Republic. The Americas did not even face any serious opposition when they declared independence as England was too focused on its internal struggles.

Skip forward to the 20th century and the Monarch of the Anglo-French Kingdom has been focused on staving off a revolution for a long time now. It stays neutral in the first World War and when the second breaks out, it simply does not have the industrial base to fend off the German invasion. The conquest of Ireland is inevitable at that point, with the German air force flying uncontested over Dublin and Belfast.

Without a bridgehead in Europe, the United States sees no path to victory and while they are officially at war with Germany after the declaration of war on its ally Japan, in practice the two countries leave each other alone until the United States defeats Japan and they sign a peace agreement.

The world is now shared between 3 superpowers: Germany in Europe and Africa, the United States in the Americas and the Pacific and the Soviet Únion in Asia.

There is a sizable German presence on the Atlantic coast, but otherwise Ireland is again left in peace and mostly ignored. War will break out soon over the Germans' insistence on replacing Guinness with "proper beer".

  • $\begingroup$ You're assuming there would be a second world war if the Anglo-French Kingdom stayed out of WWI. Which seems odd as you don't provide any reason for germany to lose the first war, thus never triggering the conditions that saw to the rise of the NSDAP. $\endgroup$ – Doomfrost Feb 21 '18 at 8:57
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    $\begingroup$ @Doomfrost You are right, and that part is the hardest to even guess at, but until the atom bomb, wars broke out rather often. The german part is mostly to drive home the point that England would likely have been in a much weaker position, and as a consequence, Ireland would be more vulnerable to aggression as well. With the technological advancement of the 20th century, Ireland is not that remote anymore and a strategic location if Europe vs America wars happen. $\endgroup$ – Cyrus Feb 21 '18 at 9:05
  • $\begingroup$ I do agree that war was rather common. However a weak England is not very interesting to a major european power. It has no natural resources that are really interesting and it's on an island, so it's bothersome to invade. If England had no major colonial holdings in this timeline it would likely not enter into a clash with Germany. Same goes for Ireland, it is of very little strategic interest unless it has the industrial and military resources to threaten Atlantic trade. $\endgroup$ – Doomfrost Feb 21 '18 at 9:34
  • $\begingroup$ The Irish figure out how to make ammunition for the guns they have, and invest massive time and energy in replicating (even basic) versions of the advanced assault weapons, fueling an early industrial revolution based in Ireland. Fast forward to 1790, the British isles have been renamed to the "Irish isles", Scotland keeps it's independence, the British royal family are hiding in Germany and the English parliment are granted home rule but takes its lead from the Dáil in Dublin. I like this alternate history :) $\endgroup$ – Binary Worrier Feb 21 '18 at 11:12

What exactly are the time travelers giving to the Irish?

  • You mentioned assault weapons. M4, AK-47 or 74, Sten, SA80? Those might actually be the wrong weapons for the mission, but perhaps the time travelers can't choose. How about a bolt-action rifle? Assume that they're delivering several thousand weapons.
  • Then they need ammo. The basic instruction how to use a weapon requires 100 rounds, give or take. Proper marksmanship requires thousands. Add the ammo for combat, and allow for the usual fog of war -- ammo crates delivered to the wrong unit, discarded during a hasty retreat, etc. Millions of rounds. It would really help if all weapons fire the same ammo.
  • Are they going to supply all the ammo or will they bring the basics of a production line? Difficult for modern guns, perhaps easier for 19th century designs.
  • Then there is the question of training. Just the use and maintenance of the weapons, or a more general course in modern warfare? Will the recruits and the generals understand and adopt small unit tactics?

If the time travelers are limited in the amount of material they can bring and the number of instructors, perhaps a few sniper rifles and a few mortars would be a better deal than lots and lots of assault weapons. Plus maps, radios, and small drones or ultralight aircraft.

What tactics are the Irish going to adopt? If they fight a stand-up battle, the Fuzzy Wuzzy Fallacy will come up. Even with AKs, the Irish might not engage the Brits beyond effective British range, and then numbers start to matter. A musket ball can kill a man with an AK just as well as it can kill a man with a musket, and the Brits have more strategic reserves. Besides, how long until they have a few assault weapons, and some traitor to teach them?

So a single "arms drop" might not change history all that much. Sustained aid is another issue.


Many of the answers have made excellent points, but one which has not been given enough weight is the fact that the Irish are disunited and split among warring clans and factions, most of whom hate each other more than the English (but the English are currently a more pressing problem).

If the English can figure out what is happening soon enough (the Irish have powerful infantry small arms) they may retreat to fortified positions and dig in. Without English armies moving out of the Pale and into the Irish countryside, how long will it take for the Irish to start using their wonderful new weapons to settle scores amongst themselves. The English will be delighted and sit back and wait for the more powerful Irish forces to self destruct and smaller Irish groups to come (with their new guns) asking for help against their other Irish enemies. The English now get a good look at a firearm from the future and begin the work of reverse engineering. While they may not be successful (they need to tools to make the tools), they are going to learn enough to jump start the Industrial Revolution. England will become far richer and more powerful than they were in OTL, being able to defeat the French in the "Seven Years War" in a much shorter period of time and start the growth of their global Empire far earlier.

This also means the United States never becomes an independent nation, and the conditions that set up the Napoleonic Wars, or WWI and II never happen. There will be wars and revolutions, but they will play out much differently.

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    $\begingroup$ Agreed on the industrial revolution starting 110 years early. Historians debate as to exactly why the industrial revolution started in England/Britain rather than e.g. Germany or Belgium. But whether the deciding factor was secure property rights, the presence of coal in Northern England and South Wales, or the growing empire overseas, that factor is almost certainly still present in the altered timeline - only now reinforced by a forceful demonstration of what can be achieved. In the face of such overwhelming power, the liberal and constitutional tradition in Britain will be drowned out. $\endgroup$ – Lostinfrance Nov 30 '15 at 7:46
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    $\begingroup$ I think the English might even look to getting some of the Irish with the automatic weapons to defect by offering promises of land and wealth. $\endgroup$ – Dave Halsall Nov 30 '15 at 11:35

"They don't want to give the historical Irish a permanent huge military advantage over everyone else"

It won't be permanent. I doubt it will last for more than a few months after they run out of ammunition. More fundamentally, the 17th century people - Irish, English, Scottish, Protestant and Catholic - have all now had a practical lesson in how to leapfrog 365 years of evolution of firearms design. Nothing can stop some of these weapons from being captured. Some of the people the time travellers have trained will also be captured, or will change sides bringing with them this valuable item to trade. The Cromwellian side can also pick up and observe empty cases and discarded ammunition.

True, Cromwell's army can't replicate the assault rifles, lacking the intervening development of metallurgy, among other things. But they know know it can be done and that's a huge timesaver. Soon the network of letters among scientific men will spread that knowledge all over Europe, Protestant and Catholic. The terrible European wars of religion just got yet worse.

External fixed bayonets can be implemented immediately. The stock design can be copied. Rifling was known at that time but not used that much because it's difficult to implement; now they know it's the way to go. Ditto breech loading. Ditto the use of drawn brass for the manufacture of cartridges. Ditto the principle of percussive cartridges.

If they start looking for fulminates they'll find them. In our timeline, fulminates were discovered as early as 1800 and first used in firearms in 1807, so it's not a huge leap.

The question is, who can first exploit this new knowledge on a large scale? It isn't the Irish. For all the bravery of the resistance, they were chronically disunited, poor in resources and from a society that compared to contemporary England was almost entirely lacking what we would now call technical infrastructure. However there is one person at that time and place who we know from history had the ability to take a bad military situation and turn it around by innovative tactics, unprecedented advances in logistics and determined generalship … Oliver Cromwell.

  • $\begingroup$ I feel the need to state that my ancestors were Irish Catholics and I hold no love for Cromwell. But there's no denying his abilities as an military organizer. $\endgroup$ – Lostinfrance Nov 27 '15 at 20:38

If I read you correct what you're asking is essentially: what would happen if Ireland was liberated from England in the 17th century, in a way that as soon as the deed has been done, any traces of the deed in terms of knowledge or artifacts that may have come from the "future" is erased; i.e. no influence on technology at all.

In my humble opinion? Not a lot. England will struggle a bit longer before getting Ireland under it's control again -- once Ireland loses it's technological advantage it will quickly fall prey to England, which, based on how England has treated other rebellious subjects, will likely let bricks rain down on the Irish for trying to be free in the first place. Once they've been stomped into the ground by, the much larger, wealthier, advanced and coherent, England, the fighting will likely be over for a few generations. I would not consider it unlikely that Ireland would be annexed by England, erasing it as a country in it's own right, turning all Irishmen into Englishmen.

  • $\begingroup$ Bear in mind that Ireland being annexed by "England" (later to become the UK) is what happened in our timeline until 1921 or 1937 depending on how you define full independence. I suppose the question is whether the annexation would "stick" in Southern Ireland. Perhaps it would, in the way that Native Americans are now Americans. (In real life it is often forgotten, or considered impolitic to mention, how many Catholic Irish were genuinely loyal to the United Kingdom of Great Britain and Ireland, as it then was.) Interesting to speculate how, when and if Catholic Emancipation would happen. $\endgroup$ – Lostinfrance Nov 30 '15 at 8:07
  • $\begingroup$ Northern-ireland It is a member state of the UK, but it is easy to get confused about this. No part of Ireland has ever (to my knowledge) been annexed by England or any other country. If Ireland was to be annexed there would no longer be an Ireland! $\endgroup$ – Clearer Nov 30 '15 at 8:58
  • $\begingroup$ OK, I shouldn't have called it an annexation given the Act of Union of 1800 was promoted at the time as measure designed to bring reconciliation after the rebellion of 1798. But wouldn't you say that Ireland was effectively annexed by England when it came under the English crown? I certainly agree that the jump-started England/UK of the altered timeline is more likely to simply annex Ireland, and other places too, feeling no need to leave even a fig-leaf of semi-independence or separate identity for the annexed territories. $\endgroup$ – Lostinfrance Nov 30 '15 at 9:17

Well first of all you have to deal with the old problem that changing the past removes your reason for changing the past... This might be harder than you think, the obvious solution is that when in the past your time travellers write to themselves in the future telling what they've done and why, and asking themselves to do the same thing.

But with Cromwell defeated, nationalism might not be a thing in the future, so your time travellers might not want to do it (in fact propaganda might make him out to be the good guy, he's a lot more popular in Britain even now than he is in Ireland). In fact they might not even have been born and if they have, might not live in the same place (so it will be very difficult for their future selves in the past to find them).

Assuming you overcome this, introducing modern technology to the past can have a kind of feedback effect. The sudden advance in technology they have might in turn advance our technology if you think they have been improving on it since then, so what the group would bring back would be even more advanced, which mean ours would be more advanced again, etc. until it reaches a critical point where it's impossible to improve in the time between then and now. History might have the Irish fighting off Cromwell with phaser rifles...

  • $\begingroup$ I'm using the time-travel model of "no paradoxes, history forks into alternate universe." And once they've destroyed English power in Ireland (at least for the "time being," from the 17th-century standpoint), they'll go "back" to the 21st century. Also, the time travelers don't teach the past-people anything about modern technology--just how to fire the guns, load the ammo, clean them, etc. $\endgroup$ – user24353 Nov 27 '15 at 9:56
  • $\begingroup$ ...sorry I misread, I thought you were letting them keep them (just hoping they run out of bullets).. Is this the case?. Just showing them the weapons is enough to get them thinking about what's possible, and letting them keep them gives them the opportunity to reverse engineer. (and, for example, figure out how to make more bullets) $\endgroup$ – colmde Nov 27 '15 at 10:24
  • $\begingroup$ After reading all these thoughtful comments, I'm thinking of asking the question with the same time-travelers, but a different strategy. Should I start a new question for that? $\endgroup$ – user24353 Nov 28 '15 at 6:42
  • $\begingroup$ @user24353, a question along the lines of "Guns aren't enough. What else can my time travellers do to change [insert historical outcome to be altered here]? would certainly interest me, although I can't speak for all Worldbuilding SE users. You might like to take a look at this earlier question and its answers: worldbuilding.stackexchange.com/questions/18451/… "Travel back in time and rise to power". In it someone mentions "Poul Anderson's classic The Man Who Came Early". $\endgroup$ – Lostinfrance Nov 29 '15 at 9:08
  • $\begingroup$ @colmde, There's yet another type of feedback effect to consider. In the altered past the people of that time can guess that the explanation for all these strange guys appearing from nowhere with wonder-weapons is that they're from the future. So they develop time travel earlier than they did in our timeline. Eventually, unless there is some mechanism to stop it, you get a situation where time travel interventions take place earlier and earlier and there is no such thing as stable history. $\endgroup$ – Lostinfrance Nov 29 '15 at 9:19

So the historical Irish will soon run out of bullets, etc., that are compatible with assault weapons

I think you underestimate humans. You need around 10 cartridges to understand how they work, how they are build and figure out how to make them.

Then you will have problem with propellant. The one from 17th century would be deadly if used in modern cases so they would need to focus on "inventing" the proper one.

Congratulations, not only you speed up the chemistry revolution by almost two centuries but the merits you gave to metallurgy reflects greatly in the everything that need to be pressed. Your time travellers would bring the industry revolution to Ireland in the 1650.

  • $\begingroup$ so if i give you 10 bullets and an 18th century village blacksmith you can fabricate precision cartridges AND percussion caps? Nope. Just nope. $\endgroup$ – Burki Dec 20 '16 at 14:22
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    $\begingroup$ 17th century. and no village blacksmith. I'm talking scientist hired by the Irish to "crack" the cartridge. They do the sections, they write how they work. Then they try to imitate the build, think about technology needed to achieve what they aiming for. Yes, it make them few months or even years to do it properly but the achievement they make on the way would effect whole world greatly. $\endgroup$ – SZCZERZO KŁY Dec 20 '16 at 14:41

They would die of smallpox. In return, they might kindly donate to the 17th century's world some interesting strains of flu and whatever would make the jump from them to the nearest down-time host.

and when some of the Irish wind up going back to fighting each other

Fixed that for ya.

In the end you'd probably be better off with snipers or volunteers willing to die during close range assassinations simply shooting Cromwell and few key figures in England (other problems there). Barring that, your training group would snowball into a battalion transported by the time machine of stadium size. Train the Irish? Sure, your characters are fluent in temporal Gaelic to explain, right? If not, you need to add interpreters or have Gaelic speaking instructors, unless you're willing to bet on Irish wanting/being able to learn in the language of Sassenach, which again is something the instructors have to learn/have interpreted (English hasn't changed that much, but enough).

And that's just instructors, you'd need plenty of REMFs for upkeep & repair, since even the basic training should take at least few weeks (NATO standard is 6 months, 'nas mnogo' armies still tend to have at least 6 weeks) and locals should not be used for this - commerce with the enemy was the time's norm, Spanish bought gunpowder from Dutch cities while marching against etc.


What would happen if time travelers brought modern assault weapons to the 17th century? We'd screw that century up even as we screw up our own. If we can't live wisely and justly in the time that's been given to US, what business do we have going into the past? Arrogance, greed.....great space/time continuum "exports".


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