How did the First World War start?

By the summer of 1914, Europe was in a crisis. Just a few weeks before, Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, had been assassinated in Sarajevo by a Serbian-backed terrorist. Now, the continent’s largest armies were mobilising against each other with new nations joining the fight seemingly every week. The world watched with bated breath as Europe marched to war. So what happened? How did a seemingly irrelevant local conflict in South-East Europe become a World War? And why did Britain decide to get involved?

By the summer of 1914, Europe was in a crisis. Just weeks before Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, had been assassinated in Sarajevo by a Serbian-backed terrorist. Now just a few weeks later, the continent's largest armies were mobilizing against each other with new nations joining the fight seemingly every week. The world watched with bated breath as Europe marched to war. So what happened? How did a seemingly irrelevant local conflict in southeast Europe become a World War? And why did Britain decide to get involved?

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When people ask how the First World War began it's often couched in terms of a domino effect, a series of events that were almost preordained, but what I would say is that if anyone had suggested in June 1914 in Britain that World War might be about to break out and they would be met with disbelief really.

Britain hadn't fought a war on the continent since the final defeat of Napoleon at Waterloo, 99 years previously. Rather than a war in Europe, Britain was primarily occupied with its own internal affairs.

As the 20th century dawned Britain is one of the greatest powers on earth, it rules over this vast global empire. I mean it's so big that every fourth person on earth owes its allegiance to the British crown.

The Briton was the world's merchant sailor, his flag encircled the globe sixty percent of the vessels on any ocean were his.

The lifeblood of the British Empire was the sea. The Royal Navy policed the waves so that its merchant ships could trade across the globe. This brought the British Empire vast wealth, but not all of its citizens were able to share in it. Many overseas subjects were demanding greater freedom from the empire to control their own affairs, while at home domestic issues threatened to boil over.

There's this huge inequality of wealth that underpins British life at the turn of the 20th century. Only two-thirds of men have got the right to vote, absolutely no woman has the right to vote. So I'd say by the time you get to 1914 this is quite a volatile country.

The most divisive issue, however, was that of Home Rule for Ireland. Some people in Ireland wanted to be ruled from Dublin rather than Westminster, while others were bitterly opposed to this, including some vocal British politicians and a sizable contingent in the north of Ireland who considered themselves to be British. As the Home Rule Bill made its way through parliament, rival militias began to arm themselves on either side of the issue.

There is a very real threat that this is going to spill over into violence in the summer of 1914 and so to suggest to people in Britain that the conflict that's about to occur will come from Europe rather than from Ireland most people would have been very very shocked to hear that.

But while domestic tensions were rising in Britain, new tensions were coming to the fore in Europe. Germany was the new kid on the block with big ambitions. After defeating France in the Franco-Prussian war of 1870, the most powerful German state Prussia allied with smaller Germanic states to create a united Germany, but this new nation wanted an empire of its own.

Britain really initially admired this new nation, Britain really actually thought as a friend but imperial Germany soon began to threaten Britain's sense of supremacy. Its determination to up its industrial output, up its military strength, and most crucially for Britain build a rival fleet of warships.

German ships manoeuvre in the cold waters of the north sea.

This new German navy was a threat to Britain's naval dominance, the glue that held the empire together, and something for which Britain could not stand. That rivalry then turned into an arms race as each nation tried to outproduce the other with ever greater feats of technology. This culminated in the production of Dreadnought battleships which were seen as the nuclear weapons of their day.

That factor means Britain's now started to see Germany as a threat, by the time you get to say 1907 Europe's really split into two opposing camps.

Germany had disturbed the delicate balance of power in Europe. France, fearing this new empire on their doorstep, allied with Russia in the east. An unlikely friendship for two of Europe's most ideologically opposed nations. That then left Germany feeling surrounded and pushed them to form an alliance with the Austro-Hungarian Empire and to a lesser extent Italy. Finally, Britain and its empire, afraid of German domination on the continent, drifted closer to France and Russia, though without going as far as forming an alliance.

You've got Germany Austria-Hungary and Italy and you've got France Russia and to some extent Britain. There's still no immediate reason for war between the two, it would take a crisis to turn tensions into an armed conflict.

And that crisis came in the summer of 1914. The Balkans in Southeast Europe had been a hotbed of unrest for some time, with two wars in the preceding three years. Those wars had made Austria-Hungary's neighbour Serbia much larger, prompting tensions between the two nations to rise even further. When Archduke Franz Ferdinand was assassinated in June by a Serbian-backed terrorist, Austria-Hungary felt it had no choice but to assert its dominance.

Austria-Hungary sets out to punish Serbia it wants to quash support for Serbian nationalism. It's encouraged by its ally Germany. So after Serbia failed to meet the terms of a very draconian ultimatum Austria-Hungary declares war on Serbia and this act of war this stirs up these old tensions and anxieties right across the continent because it draws in supporters and allies on both sides.

When Austria-Hungary declared war on Serbia Russia came in to back the Serbs in defence of a fellow Slavic nation. When Germany, in support of its ally, then declared war on Russia that brought France into the war on Russia's side. Italy however did not join the war, as its alliance with Germany and Austria-Hungary was a defensive pact. In a matter of weeks then Europe's largest powers were primed for war, but Britain was still in two minds over whether it should be involved.

It agonized over whether to support Russia and France. I think at the heart of Britain's anxieties it came down really to Britain fearing German domination of Europe because if a victorious but hostile Germany dominated the continent and threatened Britain's position in the world that was just intolerable for Britain.

The tipping point came thanks to Germany's war plans. Hoping to defeat France quickly before Russia had a chance to mobilize her forces, Germany attempted to skirt around the French defences in Alsace-Lorraine by attacking through neutral Belgium, a country Britain had sworn to protect.

On the 4th of August Britain issues an ultimatum to Germany which is ignored, which ends in Britain declaring war on Germany and by Britain declaring war on Germany that also means its global empire is at war and you have a conflict set up that becomes very rapidly a world war.

The causes of the First World War are complex, they're still debated to this day. The nations didn't realize it at the time, but their attempts to defend what they perceived as their own national interests created a war that would shape Europe for decades to come. Most participants expected the war to be over by Christmas, but as we know the reality was very different.

The First World War became what we would call a total war. These nations pitted against each other, millions of men fighting on land, on the sea, in the air, modern weaponry causing mass casualties and ultimately the war broke the empires of Germany, of Russia, Austria-Hungary, it forced the USA onto the world stage and the war also laid the seeds for future conflict in places like the Middle East. So it ultimately defined the shape of Europe and the world in the 20th century and this is how it all began.

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