The assassination of the Austrian archduke was, considered in the context of all Europe's near-explosive politics, a relatively minor event. So how did it cause such a major war?

  • 71
    The assassination was not the cause of World War I. It was the excuse for World War I, or if you're feeling generous, it was the trigger for World War I.
    – Mark
    Dec 15, 2016 at 6:14
  • 6
    I recommend the YouTube channel "The Great War", which four first video explained in details the situation prior to WWI
    – Luris
    Dec 15, 2016 at 9:45
  • 4
    One can argue that it also "caused" WWII if, e.g., one follows through to the Treaty of Versailles and considers how its consequences contributed to later conditions in Germany. Attempting to assign "a cause" to a very complex event is tricky. Dec 15, 2016 at 12:54
  • 32
    The archduke was the heir apparent to the Austro-Hungarian crown and his father the emperor was a very old man. His assassination was not a minor event.
    – fdb
    Dec 15, 2016 at 13:35
  • 20
    In Grade 8 I had a test question that actually said "What caused World War I? Use other side of page if necessary". My family adopted that instruction as an in-joke on questions seeking simple answers to very complicated things. Dec 16, 2016 at 13:18

5 Answers 5


The assassination itself did not cause the war — it only caused the first declaration of war in World War One.

What really happened between the assassination (June 28) and the eruption of war (August 1 & 2) was this:

  1. Convinced that anti-Austrian propaganda coming out of Serbia had led to the assassination, Austria, or rather Austro-Hungary, declared war on Serbia on July 28.
  2. Russia agreed to help Serbia, another Slavic nation, and
  3. Germany, an ally of Austria, declared war on Russia.
  4. Then France agreed to help Russia, and
  5. Germany declared war on France.
  6. The next day, Germany, putting into effect a long-planned scheme to conquer France, sent troops through neutral Belgium to attack Paris.
  7. Britain insisted on Belgium's neutral rights to be respected, but the German chancellor said that the 1839 treaty guaranteeing Belgian neutrality was a "scrap of paper". So Britain came to the aid of Belgium by declaring war on Germany, and the minor countries of the world soon followed suit.

It was by this series of steps that the minor assassination caused the first war to be fought on a global scale.

  • 4
    More info on the first point which started it all. During this time Austria was a country with many ethnic minority groups, among them the Serbs. The assassination was conducted by a group of Serb nationalists which were viewed as terrorists in Austria. Austria gave Serbia an impossible ultimatum which was impossible to accept. After Serbia declined the ultimatum, Austria declared war on them.
    – jigglypuff
    Dec 15, 2016 at 5:59
  • 37
    Might mention that it wasn't Austria, but rather Austro-Hungary., not modern Austria. This Empire went from Tyrol to Transylvania and Bosnia to Prague/Kracow. It wasn't just a puny little murder either. The murder meant that the Empire would be split once the current ruler died because the murder was on his only legitimate heir (meaning that the Empire would most likely be in a civil war , and quite possibly be split up)
    – Oak
    Dec 15, 2016 at 7:31
  • 12
    Also, the Germans were looking for a fight to try and increase their colonial holdings; Britain was looking to put the upstart Germany back in place; France had bad blood with Germany following the 19th century; Russia and Austro-Hungarian empire had serious internal issues and hoped a war would divert their domestic tensions. The assassination was merely the match to the powder keg of international tension
    – user13123
    Dec 15, 2016 at 9:37
  • 21
    @Oak: there was an established line of succession after Franz Josef, and Karl took the throne when Franz Josef died two years later. Yes, there were major ethnic tensions in Austria-Hungary, but it's simply incprrect that Franz Ferdinand was the only legitimate heir, nor that the Empire would necessarily split after Franz Josef's death. Dec 15, 2016 at 10:04
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – T.E.D.
    Jan 26, 2017 at 1:54

Whether the assassination of an Arch-Duke is a 'minor event' is a matter of opinion. In this particular case it was also the assassination of the Heir to the Austro-Hungarian throne, the Inspector of its armed forces (implying probable role as Commander in Chief in the event of war) and a close relative of the Emperor. Arch-Duke Franz-Ferdinand was all of those things. So the murder of the Arch Duke was a big deal from Austria-Hungary's point of view. Austria-Hungary was still considered a major power in those days, with a proud history.

However, Austria-Hungary's position as a great power, and even its continued existence, was threatened. It had lost wars to France and Italy in the 1850s and Prussia in the 1860s, and as a multi-ethnic empire in an age of nationalism it was threatened by possible break-away movements among its many different nationalities. It could not therefore be seen to be weak in the face of terrorist assassins from what were generally considered more minor and backward peoples like the Serbs and Croats.

That may help explain why the assassination led to war between Austria-Hungary and Serbia. Why did it lead to a general European, and eventually World War?

Well, people write books about the causes of the First World War so this is very far from a complete answer.

However, it had been quite common in the Seventeenth and Eighteenth centuries, and Napoleonic Wars, that once a War began somewhere in Europe other powers joined in if they saw an advantage/ a need to stop the largest power getting any more powerful from their own security. E.g. the Wars of the Spanish and Austrian successions in the Eighteenth Century and French Revolutionary and Napoleonic Wars 1792 - 1815, when other powers often co-operated to stop France becoming too dominant, or used the fact that others were occupied fighting each other to grab territory.

By 1914 the power that threatened to dominate the rest was Germany, so the choice for the others was whether to combine to resist German dominance (as Britain, France and Russia did) or to fall in with it as a junior partner on what they hoped would be the winning side (as Austria-Hungary and Turkey did).

A significant issue that I believe is linked to this is why, against precedent, before 1914 many of the Great Powers had formed long-term treaty alliances even in peacetime (as France had with Russia, Austria-Hungary had with Germany and Britain with Japan) by which they were committed to support each other in the event of a major war. This made it more likely that a war between a couple of countries would spread.

Added to which:

German war plans hinged taking advantage of their central position and good railway and road networks to assemble their army and strike before the other powers were ready, so they would not wait around for long discussing possible diplomatic compromises.

Britain (then under a relatively pacific Liberal government) was genuinely ambivalent about whether it would or should stand by France in the event of war; consequently there was not a clear enough warning to Germany that Britain would fight on the French side if Germany started a war.

  • 1
    It was a minor event **considered in the context of all Europe's near-explosive politics **. Dec 15, 2016 at 15:19
  • 2
    @georgestrieby and a spark in an old galleon's powder room is a very minor event. The consequences, not so much... This answer goes some way to explaining why Europe was a powder keg just waiting for a spark. The assassination was just the spark.
    – Leliel
    Dec 15, 2016 at 17:08
  • 2
    Re the argument that there were so many factors potentially leading to war that it had become almost inevitable, I can remember writing an essay like that at school with a long list of 'causes' of the war (colonial rivalry, Anglo-German Naval rivalry etc.) However, I now think one could probably have come up with a similar list of potential causes of a great war at any point in the preceding century, without any such war usually actually occurring. The emphasis on finding causes of historical events is legitimate but can also make things seem more inevitable than they are.
    – Timothy
    Dec 15, 2016 at 17:29
  • 3
    @georgestrieby It was a major event because of Europe's near-explosive politics, and it took place right in the middle of those politics.
    – user207421
    Dec 15, 2016 at 23:53

The war was already built-in, because Germany was faced with a strategic conundrum/objective circumstances:

  • If Russians enter the war, Germany risks losing it, fighting France and Russia on two fronts

  • Russians (if I recall the contemporary estimates correctly) would take ~2 weeks to call up its forces and actually be able to attack.

  • As such, Germany's only (seemingly, at least) viable option was to attack France immediately, and force it to surrender, very quickly, before Russia had a chance to offer a second Eastern front.

Therefore, the moment Russia acted aggressively past Arch-Duke's assassination and Austrian saber-rattling towards Serbia, Germany basically had only one path forward: attack France ASAP and hope to implement the Schlieffen Plan and take France out of the war before Russia got there.

As German's government saw it, the only other alternative was to wait for Russia to activate its army, attack Austria, and then together with France attack Germany.

  • 2
    Germany had two paths forward: as an alternative to attacking France, they could decline to declare war on Russia. Austria-Hungary would be unhappy, but it would keep Germany out of the war.
    – Mark
    Dec 15, 2016 at 22:48
  • 1
    @Mark - nope. That would make France attack Germany (while it's weakened by war with Russia), to pre-empt later attack by Germany once it offs Russia.
    – DVK
    Dec 16, 2016 at 3:02
  • 3
    if France attacks Germany without Germany first declaring war on Russia, Germany is free to turn its full force on France.
    – Mark
    Dec 16, 2016 at 3:16
  • 1
    @Mark - you're forgetting... Germany just committed most of its army to the Eastern front. What do you think happens if they take that army and move it west against French attack? (oh, and let's not forget the logistics of moving samesaid army from front to front taking time).
    – DVK
    Dec 16, 2016 at 3:19
  • 3
    @DVK Germany cannot be "weakened by war with Russia" if they never go to war with Russia.
    – Wlerin
    Dec 18, 2016 at 21:09

The reason was the system of alliances.

The conflict started as a conflict between Austria Hungary (who wanted revenge for the killing) and Serbia.

But Serbia was allied with Russia, Russia was allied with France, and France was allied with Britain. Also, Austria-Hungary was allied with Germany.

So when Austria-Hungary threatened Serbia, Russia declared war on Austria-Hungary. Germany tried to "warn off" Russia, but ended up at war instead. France declared war on Germany, using the occasion to get revenge for 1871.

In theory, Germany could have stood on the defensive against France and joined Austria-Hungary against Russia, but another poster pointed out the dangers of such a poster, a belief that was widely held (on both sides) at the time.

So when Germany took the offensive by attacking France via Belgium, Britain went to war against Germany to protect Belgium.

  • Re your 3rd para, on alliances: did Serbia actually have an alliance with Russia? I was not aware of that, although, as was still true in late twentieth century conflicts the Serbs had in Bosnia and Kosovo, Russia tended to sympathise with the Serbs as fellow Slavs and Orthodox Christians. Also, not strictly true that "France was allied with Britain". They agreed 'the Entente Cordial' to resolve specific disputes between them and promote co-operation, so there was some expectation they would be on the same side, but no actual alliance. Hence Germany could hope Britain might stay neutral.
    – Timothy
    Dec 16, 2016 at 17:23
  • @Timothy: In February, 1914, the Russian Tsar told the Serbian foreign minister, for Serbia we will do anything. mentalfloss.com/article/54849/… Russia considered the Serbians fellow Slavs.
    – Tom Au
    Dec 16, 2016 at 18:01

The simplest answer might be something like "the assassination itself caused only the Austro-Hungarian declaration of war against Serbia, not the World War itself which was the result of a chain reaction and long underlying factors". To illustrate this, I could add something based on a very relevant comment by user Michael.

"According to Erenburg, when France was mobilized in 1914 some small store owners put out signs on their doors: "out for the annual mobilization." Major European countries were itching for a war, it just needed a pretext. – Michael Dec 21 '16 at 18:57"

This seems to be backed up by an article I found on the internet a few years ago, which said that in France old mobilization posters were found on which the date 1914 was discovered to have been originally "1904" but changed into "1914". This would suggest France had been preparing for war long before it actually happened (I may have saved the article at the time or I may have not - I have no idea and it would be difficult for me to find out at the moment, but a search might resolve this).

  • 2
    1) Answers should not - usually - comment on other answers. 2) Quotes should be sourced, and 3) assertions - like the 1904 assertion - really should be sourced.
    – MCW
    Oct 10, 2017 at 13:49
  • Ah, the famous "I read on t'Internet"! That couldn't, perhaps, be a reference to the French National Printing Office reference number for the mobilisation poster - "3-148-1904", by any chance? Oct 10, 2017 at 13:58
  • @sempaiscuba - sorry to say, but I really have no idea. I only know I did read it in an article, a year or maybe a couple years ago. The article said the posters were older than they were supposed to be, as the original supposed year - or date - of mobilization was shown to have been 1904. I really do think the fact such a thing came to light so late after the facts (just like the Lusitania having been a munitions and weapons transport, like the Germans were claiming to defend their sinking of a purported passenger ship) does tell us something about history. Oct 10, 2017 at 15:39
  • @Mark C. Wallace - I guess I should have written it as a comment, but it really was also meant as an answer to the question; and indeed, I admit it could be taken as a mere assertion. It certainly does back up Michael's comment about the French store owners' "out for the annual mobilization", which is revealing in its own light as it indicates this happened every year again. Oct 10, 2017 at 15:41
  • @ObiwanKeNoobie If you look at the picture of the poster, it doesn't have a printed date, so it wouldn't have needed to be overwritten. Which does rather call the veracity of the "fact" into question. Oct 10, 2017 at 18:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.