On June 28, 1914, a member of the revolutionary group Young Bosnia assassinated Archduke Franz Ferdinand. The Archduke was heir apparent to the throne of Austria-Hungary, which had annexed Bosnia and Herzegovina several years earlier. Young Bosnia was trying to overthrow Austro-Hungarian rule over the region and had acquired weapons for a revolution with the help of Serbian nationalists. Austria-Hungary discovered this connection and declared war on Serbia a month after the assassination.
Why this regional conflict escalated into World War I – which killed some 40 million soldiers and civilians – has been a matter of debate since its end. While there is no single answer, part of the reason the war has escalated to such an extent has to do with a complex web of alliances that European nations have made with each other over the years. decades before the war.
These alliances created a balance of power in Europe that some hoped would prevent war. Yet for many countries, these alliances made them feel they had no choice but to join in a growing international conflict.
WATCH: World War I The First Modern War on HISTORY Vault
Alliances before World War I
World War I had two main factions: the Central Powers, which included Germany, Austria-Hungary, Bulgaria, and the Ottoman Empire; and the Allies, which included France, Britain, Russia, Italy, Japan, and later the United States. With the exception of Italy, which switched sides, most of these alliances have their roots in pre-war agreements.
Much of the animosity behind both sides of World War I dates back to the Franco-Prussian War of 1870, in which the German states (led by Prussia) thwarted France’s attempt to reassert its dominance. on the continent. After the war, Prussia and other German states united to form the German Empire and allied with neighboring Austria-Hungary. In 1882, the newly unified state of Italy joined Germany and Austria-Hungary, forming the Triple Alliance.
Over the following decades, European empires continued to create alliances and informal agreements as they vied for power and colonial territories around the world.
“France was looking for an ally against Germany,” says Jonathan Casey, director of the Edward Jones Archives and Research Center at the National WWI Museum and Memorial. In the 1890s, France formed an economic and military alliance with Russia, whose empire posed “a threat to Germany’s eastern border”.
France and Russia have gradually established good relations. France’s historical rival, Great Britain, resulted in the Triple Entente between the three nations. This “entente,” or understanding, was not a military alliance, but it helped establish competing camps in Europe.
“The alliance system was basically an attempt to try to form collective security,” says Richard Fogarty, a history professor at the University of Albany. “But that meant it replaced a system in which a whole group of states competed individually with one in which states competed in, ultimately, two major alliances. And that set the stage for war.
READ MORE: 8 events leading up to World War I
How alliances played out during the war
Young Serbian recruits, c. 1914. After the outbreak of World War I, Serbia repelled a succession of Austrian invasion attempts before succumbing to a combined offensive launched by Germany, Austria and Bulgaria the following year.
The Impression Collector/The Impression Collector/Getty Images
After the assassination of Archduke Ferdinand comes the July Crisis. During this month, Austria-Hungary sent a list of demands to Serbia. Serbia, knowing that it could expect support from Russia as a Slavic state, refused to give in to one of the main demands. Austria-Hungary confirmed to Germany that it would receive its support if it went to war, and Russia did the same with France.
“I think most of the people involved believed or hoped that by saying and knowing they had the support of their allies, they could actually avoid war,” Fogarty said. “In other words, ‘Austria won’t dare do anything to Serbia if it knows that Russia is behind it.’ And then the Austrians think: ‘Russia won’t dare to do anything to Serbia if they know that the Germans will get involved “” and so on.
The declarations of war begin
But on July 28, Austria-Hungary declared war on Serbia. Over the next week and a half, Germany declared war on Russia and France, Britain declared war on Germany, and Austria-Hungary declared war on Russia.
The justification Britain gave for going to war didn’t even have to do with its Triple Entente with France and Russia – it had to do with the much earlier Treaty of London (also called the First Treaty of London) of 1839 which obliged Belgium to always be a neutral state. When Britain entered the war, it argued that Germany had violated this treaty by invading Belgium.
READ MORE: Was Germany Doomed in WWI by the Schlieffen Plan?
Over the next four years, many other nations went to war. Japan joined the Allies at the end of August 1914. In November, the Ottoman Empire joined the Central Powers. The following year, Italy entered the war to fight vs Germany and Austria-Hungary, with which it had previously formed an alliance. In 1917, the United States joined the Allies.
The 1919 Treaty of Versailles which enshrined the terms of the end of the war placed most of the blame for the conflict on Germany. But the reality of why so many nations got involved in the war is much more complicated – and it’s something people have been debating ever since.
As Fogarty puts it, “What happens at the end of the war is everyone wonders, how the hell did this happen?”
