In 1903, a military coup in Serbia killed the king and installed a fiercely nationalistic leadership. Serbian nationalists were proud of their Slavic heritage, and Russia became a powerful ally in large part because of the Slavic connection between Russians and Serbs (i.e. they spoke related languages and the Russian and Serbian Orthodox churches were part of the same branch of Christianity). Russia also supported Serbia because of Russian rivalry with Austria. Serbian nationalists believed that, with Russian support, it would be possible to create an international crisis in Austrian-controlled Bosnia and ultimately seize Bosnia itself. The Serbs did not believe that Austria would risk a full-scale war with Russia in order to hold on to Bosnia.

Among the organizers of the coup that had murdered the king and queen were a group of Serbian officers who created a terrorist group, The Black Hand. In 1914, The Black Hand trained a group of (ethnically Serbian) college students in Bosnia to assassinate an Austrian politician when the opportunity presented itself. That happened in June of 1914, when Franz Ferdinand and his wife came to visit the Bosnian capital of Sarajevo. In a fantastically bungled assassination, Franz Ferdinand survived a series of attacks, with some of his would-be killers getting cold feet and running off, others injuring bystanders but missing the Archduke, and others losing track of where the Archduke’s motorcade was. Finally, quite by accident, the Archduke’s driver became lost and stuck in traffic outside of a cafe in which one of the assassins was eating a sandwich. The assassin, Gavrilo Princip, seized the opportunity to stride outside and shoot the Archduke and his wife to death.

Serbia’s assumption that Austria would not risk war proved to be completely wrong. The Austrian government demanded that Serbia allow Austrian agents to carry out a full-scale investigation of the assassination; Serbian honor would never allow such a thing. Austrian troops started massing near the Serbian border, and the great powers of Europe started calling up their troops. Germany, believing that its own military and industrial resources were such that it would be the victor in a war against France and Russia, promised to stand by Austria regardless of what happened. Russia warned that Austrian intervention in Serbia would cause war. France assured Russia of its loyalty. Only Britain was as-yet unaccounted for.

No one was completely certain that a war would actually happen (the German Kaiser, Wilhelm II, left for his summer vacation as planned right in the middle of the crisis, believing no war would occur), but if it did, each of the great powers was confident that they would be victorious in the end. A desperate diplomatic scramble ensued as diplomats, parliaments, and heads of state tried at the last minute to preserve the peace, but in the end it was too late: on July 28, Austria declared war on Serbia, activating the pre-existing system of alliances, and by August 4 all of the great powers were involved.

Thanks to the fact that Germany invaded through Belgium, Great Britain declared war on Germany and its allies. In addition to Germany and the Austrian Empire, the Ottoman Empire soon joined their alliance, known as the Central Powers. Opposing them was the Triple Entente of Great Britain, France, and Russia. Smaller states like Italy and Portugal later joined the Triple Entente, as did, eventually, the United States.

The Early War

There was a mixture of apprehension and, in many cases, enthusiasm about the onset of war among civilians and soldiers alike. Many felt that the war would resolve nationalistic rivalries once and for all, and almost no one anticipated a lengthy war. Wilhelm II anticipated “a jolly little war” and it was widely thought in France and Germany that the war would be over by Christmas. 30,000 young men and women marched in Berlin before war was even declared, singing patriotic songs and gathering at the feet of statues of German and Prussian heroes.

Everywhere, thousands of young men enlisted in the military of their own volition. There were some anti-war protests in July, mostly organized by the socialist parties in the name of socialist internationalism, but once war was actually declared those protests abruptly stopped. The most symptomatic moment of the defeat of socialism by nationalism as ideologies was the fact that 100% of the socialist parties of Europe supported their respective countries in the war, despite hard and fast promises before the war that, as socialists, they were committed to peace. Whereas pre-war socialists had argued vociferously that the working class of each country was a single, united class regardless of national differences, that internationalist rhetoric largely vanished once the war began. Wanting to be seen as patriots (whether French, German, or British), the major socialist parties voted to authorize the war and supported the sale of war bonds. In turn, the radical left of the socialist parties soon broke off and formed new parties that continued to oppose the war; these new parties were typically called “communists” whereas the old ones remained “socialists.”

War, for many people, represented a cathartic release. War did not represent real bloodshed and horror for the young men signing up – they had never fought in real wars, except for the veterans of colonial wars against much less well-armed “natives” in the colonies. War was an ideal of bravery and honor that many young men in Europe in 1914 longed for as a way to prove themselves, to prove their loyalty, and to purge their boredom and uncertainty about the future. A whole generation had absorbed tales of glory on the battlefield, of the Napoleonic Wars, the Crimean War, the Franco-Prussian War, and the conquests overseas. Depending on their nationality, they were either ashamed and angry or fiercely proud of their country’s performance in past wars. As a result, many saw a new war as a chance to settle accounts, to prove once and for all that they were citizens a great power, and to shame their opponents into conceding defeat.

The war itself began with the German invasion of France through Belgium. German tactics centered on the “Schlieffen Plan,” named after its author, Field Marshal Alfred von Schlieffen, who had devised it in the first years of the twentieth century. The Schlieffen Plan called for a rapid advance into France to knock the French forces out of the war within six weeks. Subsequently, German troops would be whisked back east via railroads in time to engage Russia, as it was believed that it would take the Russians at least that long to mobilize their armies. It not only called for rapid mobilization, but it required the German military to defeat the French military at an even more rapid pace had the Prussian forces forty years earlier in the Franco-Prussian War.

The first taste of the horror of the war to come was the German invasion of Belgium. Belgium was a neutral country leading up to the war, and German planners had expected Belgium to surrender swiftly as German troops advanced rapidly toward France. Instead, Belgian soldiers fiercely resisted the German invasion. In turn, German troops deliberately massacred civilians, destroyed towns, and raped Belgian women. Thousands of Belgian refugees fled to Britain, where they were (to the credit of the British government and civilians) welcomed and housed. The bloodshed shocked the sensibilities of the French and British reading public and emphasized the fact that the war might go very differently than many had first imagined. Britain swiftly declared war on Germany.

While the first few weeks of the German invasion seemed to match the ambitions of the Schlieffen Plan, they soon ground to a halt. A fierce French counter-attack stopped the Germans in Belgium and Northeastern France in late September. Simultaneously, the Russians surprised everyone by mobilizing their forces much more quickly than expected, attacking both Germany and Austria in the east in late August. In the autumn of 1914 the scale of battles grew to exceed anything Europe had witnessed since the Napoleonic Wars (which they soon dwarfed). To their shock and horror, soldiers on all sides encountered for the first time the sheer destructive power of modern weaponry. To shield themselves from the clouds of bullets belched out by machine guns, desperate soldiers dove into the craters created by artillery shells. In the process, trench warfare was adopted (it was used earlier by the Chinese and to an extent by the Americans in the US Civil War).

The weapons that had been developed in the decades leading up to the war, from enormous new battleships known as dreadnoughts to high-explosive artillery shells and machine guns, had all seemed to the nations of Europe like strengths. The early months of the war revealed that they were indeed strong, in a sense, being far more lethal than anything created before. Unfortunately, human bodies were pitifully weak by comparison, and as the death toll mounted, the human (and financial) costs associated with modern warfare shattered the image of national strength that politicians and generals continued to cling to. Those generals in particular stuck to their favored, and outdated, tactics, sending cavalry in bright uniforms to their deaths in hopeless charges, ordering offensives that were doomed to fail, and calling up every soldier available on reserve.

That Christmas, in a well-remembered symbolic moment, a brief and unauthorized truce held on the Western Front between Entente and German forces long enough for French and German soldiers to climb out of their respective trenches and meet in the “no man’s land” between the lines, with a German barber offering shaves and haircuts to all comers. By then, both sides were well aware that the conceit that the war would “be over by Christmas” had been a ridiculous fantasy. Never again in the war would a moment of voluntary peace re-emerge; while they did not know it for certain at the time, the soldiers faced four more years of carnage to come.