World War I Introduction and Overview

World War I was a major conflict fought in Europe and around the world between July 28, 1914, and November 11, 1918. Nations from across all non-polar continents were involved, although Russia, Britain, France, Germany, and Austria-Hungary dominated. Much of the war was characterized by stagnant trench warfare and massive loss of life in failed attacks; over eight million people were killed in battle.

Belligerent Nations

The war was fought by two main power blocks: the Entente Powers, or 'Allies,' comprised of Russia, France, Britain (and later the U.S.), and their allies on one side and the Central Powers of Germany, Austro-Hungary, Turkey, and their allies on the other. Italy later joined the Entente. Many other countries played smaller parts on both sides.

Origins of World War I

To understand the origins, it is important to understand how politics at the time. European politics in the early twentieth century were a dichotomy: many politicians thought war had been banished by progress while others, influenced partly by a fierce arms race, felt war was inevitable. In Germany, this belief went further: the war should happen sooner rather than later, while they still (as they believed) had an advantage over their perceived major enemy, Russia. As Russia and France were allied, Germany feared an attack from both sides. To mitigate this threat, the Germans developed the Schlieffen Plan, a swift looping attack on France designed to knock it out early, allowing for concentration on Russia.

Rising tensions culminated on June 28th, 1914 with the assassination of Austro-Hungarian Archduke Franz Ferdinand by a Serbian activist, an ally of Russia. Austro-Hungary asked for German support and was promised a 'blank cheque'; they declared war on Serbia on July 28th. What followed was a sort of domino effect as more and more nations joined the fight. Russia mobilized to support Serbia, so Germany declared war on Russia; France then declared war on Germany. As German troops swung through Belgium into France days later, Britain declared war on Germany too. Declarations continued until much of Europe was at war with each other. There was widespread public support.

World War I on Land

After the swift German invasion of France was stopped at the Marne, 'the race to the sea' followed as each side tried to outflank each other ever closer to the English Channel. This left the entire Western Front divided by over 400 miles of trenches, around which the war stagnated. Despite massive battles like Ypres, little progress was made and a battle of attrition emerged, caused partly by German intentions to 'bleed the French dry' at Verdun and Britain's attempts on the Somme. There was more movement on the Eastern Front with some major victories, but there was nothing decisive and the war carried on with high casualties.

Attempts to find another route into their enemy’s territory led to the failed Allied invasion of Gallipoli, where Allied forces held a beachhead but were halted by fierce Turkish resistance. There was also conflict on the Italian front, the Balkans, the Middle East, and smaller struggles in colonial holdings where the warring powers bordered each other.

World War I at Sea

Although the build-up to war had included a naval arms race between Britain and Germany, the only large naval engagement of the conflict was the Battle of Jutland, where both sides claimed victory. Instead, the defining struggle involved submarines and the German decision to pursue Unrestricted Submarine Warfare (USW). This policy allowed submarines to attack any target they found, including those belonging to the 'neutral' United States, which caused the latter to enter the war in 1917 on behalf of the Allies, supplying much-needed manpower.


Despite Austria-Hungary becoming little more than a German satellite, the Eastern Front was the first to be resolved, the war causing massive political and military instability in Russia, leading to the Revolutions of 1917, the emergence of socialist government and surrender on December 15. Efforts by the Germans to redirect manpower and take the offensive in the west failed and, on November 11, 1918 (at 11:00 am), faced with allied successes, massive disruption at home and the impending arrival of vast US manpower, Germany signed an Armistice, the last Central power to do so.


Each of the defeated nations signed a treaty with the Allies, most significantly the Treaty of Versailles which was signed with Germany, and which has been blamed for causing further disruption ever since. There was devastation across Europe: 59 million troops had been mobilized, over 8 million died and over 29 million were injured. Huge quantities of capital had been passed to the now emergent United States and the culture of every European nation was deeply affected and the struggle became known as The Great War or The War to End All Wars.

Technical Innovation

World War I was the first to make major use of machine guns, which soon showed their defensive qualities. It was also the first to see poison gas used on the battlefields, a weapon which both sides made use of, and the first to see tanks, which were initially developed by the allies and later used to great success. The use of aircraft evolved from simply reconnaissance to a whole new form of aerial warfare.

Modern View

Thanks partly to a generation of war poets who recorded the horrors of the war and a generation of historians who castigated the Allied high command for their decisions and ‘waste of life’ (Allied soldiers being the 'Lions led by Donkeys'), the war was generally viewed as a pointless tragedy. However, later generations of historians have found mileage in revising this view. While the Donkeys have always been ripe for recalibration, and careers built on provocation have always found material (such as Niall Ferguson's The Pity of War), the centenary commemorations found historiography split between a phalanx wishing to create a new martial pride and sideline the worst of the war to create an image of a conflict well worth fighting and then truly won by the allies, and those who wished to stress the alarming and pointless imperial game millions of people died for. The war remains highly controversial and as subject to attack and defense as the newspapers of the day.

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Wilde, Robert. "World War I Introduction and Overview." ThoughtCo, Feb. 22, 2021, Wilde, Robert. (2021, February 22). World War I Introduction and Overview. Retrieved from Wilde, Robert. "World War I Introduction and Overview." ThoughtCo. (accessed May 28, 2023).