The First World War of 1914–18 was the bloodiest war there had ever been, partly because it involved the top three economic powers in the world (Germany, the UK and USA) as well as the leading imperial systems, with all the manpower they controlled. The destructiveness of the weaponry, manufactured on an unprecedented scale, was also crucial.
Another key factor was the inability of the combatants to negotiate a peaceful end to the conflict, an inability repeated in the Second World War. As a consequence, the appalling level of destruction, rather than leading to efforts to negotiate, instead contributed to a determination to devote even more effort to the fight.
The war pitted a coalition of Germany and Austria (the Central Powers) against France, Belgium, Britain, Serbia, Russia (the Allies) and Japan. In turn, each side enlisted new partners, though the Central Powers only gained Turkey and Bulgaria, while the Allies’ recruits included Italy, Portugal, Romania and, decisively, the United States (in April 1917).
The immediate cause of the conflict was Austrian aggression towards Serbia. On 28 June 1914 a Bosnian nationalist backed by the Serbian Black Hand secret society assassinated Archduke Franz Ferdinand, heir to the Austrian throne, in Sarajevo, the capital of Austrian-ruled Bosnia. Austria turned down Serbian offers of reparations and instead to go to war, intending to crush the growing nationalism within its empire.
Russia now moved to mobilize its armies, and rejected a German ultimatum to recall them. Germany declared war on Russia and then on Russia’s ally France. The decision owed much to the German high command, which feared encirclement by the alliance of France and Russia. The German general staff had prepared a plan to knock France quickly out of the war by bypassing the French fortresses along the German border and invading France through vulnerable Belgium. This action pitched Britain into the war, as a guarantor by treaty of Belgian neutrality.
The opening year saw no decisive victories, but the Germans ended 1914 with major territorial gains in both Belgium and France. So the western Allies were forced to take the offensive, both to recover ground and also to reduce the strains on Russia, which lost heavily at the hands of Germany in 1914 and 1915.
In September 1914 the Germans dug themselves into defensive positions, the Allies did the same and the Western Front was born. Its multiple lines of trenches reached from the Franco-Swiss border north-westward to the North Sea. French and British generals dreamed of making a decisive breakthrough through frontal attacks, but the military technology of the day, notably machine guns and artillery, emplaced in strong systems of trenches and dugouts, strongly favoured the defending side. The massive casualties that resulted were not matched by significant territorial gains. By the end of the war, however, new tactics, such as the use of precise artillery fire integrated with infantry assaults, proved more effective. It was these that helped the Allies to victory in 1918.
‘We were very surprised to see [the English soldiers] walking, we had never seen that before. The officers were in front. I noticed one of them walking calmly, carrying a walking stick. When we started firing we just had to load and reload. They went down in their hundreds. You didn’t have to aim, we just fired into them.’
German machine-gunner recalls the first day of the Battle of the Somme (1 July 1916)
In the meantime, the war had shed blood on an unheard-of scale. Some of the battles, notably Verdun and the Somme in 1916, were ruinously costly (over 2 million casualties between them). Although they knocked Russia out of the war in 1917–18, the Germans were outfought and outresourced by the Western allies.
The war had led to the development of massive military–industrial complexes, especially for the manufacture of guns and high-explosive shells. Control of the seas was also crucial. Germany waged a long and successful submarine campaign against Allied merchant shipping. At the same time, Allied navies, particularly the British, imposed a tight blockade on Germany, and starved it of resources. Both sides used poison gas against each other, though this was never militarily decisive.
This war appeared far removed from previous ideas of battle as a matter of individual and collective heroism. Instead, it embodied the notion that humans came second to the deadly machinery of war. The war also saw the first significant aerial bombardment of civilian targets, which led to the fear that future wars would see cities destroyed by bombers. This all contributed to a degree of subsequent anti-war feeling. However, in the immediate aftermath and on into the 1920s, many people appear to have accepted that the war had been a necessary burden, a matter of unavoidable duty and sacrifice.
‘The statesmen were overwhelmed by the magnitude of events. The generals were overwhelmed also. Mass, they believed, was the secret of victory. The mass they invoked was beyond their control. All fumbled more or less helplessly.’
A. J. P. Taylor, The First World War (1963)