What Was the First War?

The conflict was between the Sumerians and the neighboring Elamites, who lived in what is now Iran. We can't say the battles between these two nations were part of the first war ever fought — the earliest conflicts likely began 10,000 years ago in the late Paleolithic or early Neolithic periods, but we have no records from that time. Around 2700 B.C., the Sumerian king Enmebaragesi led soldiers against the Elamites and won, looting the nation in the process. It looks like the reason for the earliest war was that the Elamites were a potential threat to the Sumerians and they had resources the Sumerians wanted.

For war to exist, nations or states must retain a sense of independence and detachment from other communities. Without this independence, there is no us-versus-them mentality. As long as there is differentiation between communities, there is the potential for conflict. Nations that perceive a threat from a foreign state may initiate war in an attempt to head off future conquest. Or a community might wage war in order to access resources that another community possesses. Ultimately, war requires that we identify ourselves as belonging to one group while simultaneously excluding other people.

Let's jump ahead to more recent war history — World War I. As you may remember from history class, it was a global war that began in 1914 and ended in 1918. This monumental conflict involved most of the world's great powers, which were divided into two opposing alliances: the Allies and the Central Powers. The roots of World War I lay in a complex web of alliances, militarism, nationalism, and imperial ambitions. The assassination of Archduke Franz Ferdinand of Austria-Hungary on June 28, 1914, triggered a chain reaction of events that led to the outbreak of war.

The event that is often considered the immediate catalyst for World War I was the moment Austria-Hungary declared war on Serbia. This declaration came on July 28, 1914, exactly one month after the assassination of the heir to the Austro-Hungarian throne. The Austro-Hungarian leadership had issued an ultimatum to Serbia with deliberately unacceptable demands, seeking a pretext for war to curb Serbian nationalism and influence in the Balkans. Serbia's response was not satisfactory to Austria-Hungary, leading to the declaration of war which set off a rapid mobilization of allies on both sides.

As Austria-Hungary declared war on Serbia, the alliance system came into play. Russia, bound by a treaty to Serbia, began to mobilize its troops, which in turn prompted Germany to mobilize. The mobilization of German troops was a critical stage in the escalation of the conflict. Germany's war plan, the Schlieffen Plan, required a rapid invasion of Belgium and France to knock them out of the war quickly before turning eastward to deal with Russia. This plan was put into action, and German troops crossed into Belgium on August 4, 1914, prompting Britain to declare war on Germany due to its obligations to protect Belgian neutrality, thereby widening the war beyond the Balkans.

The Middle East became a significant theater of conflict during World War I, seeing many pivotal battles and campaigns. The Ottoman Empire, aligned with the Central Powers, faced off against the British and their allies in a series of engagements that would reshape the region's political landscape. The campaigns in the Middle East were marked by a different kind of warfare than the trench battles in Europe, involving more mobile units and guerrilla tactics, yet they were no less brutal and were still characterized by suffering heavy casualties on both sides.

The Western Front, known for its trench warfare, was the site of some of the most prolonged and deadliest battles of World War I. The opposing forces, entrenched in miles of fortifications, engaged in a war of attrition, leading to mass casualties. The Battle of the Somme and the Battle of Verdun are prime examples where hundreds of thousands of lives were lost. Here, the term "suffering heavy casualties" became a grim reality, as waves of soldiers were cut down by machine-gun fire and artillery, with little ground gained for the massive losses incurred.

The concept of mass casualties took on a new meaning during World War I. It was the first conflict where the industrialization of war became apparent, with the ability to sustain long-term armed conflict and produce weapons capable of unprecedented destruction. The use of chemical weapons, widespread disease, and the sheer scale of the battles meant that by the end of the war, millions had died. The war left a legacy of a lost generation and a new understanding of the human cost of industrial-scale warfare.

After four long years of conflict, the opposing forces of WWI were weary. The entrance of the United States on the side of the Allies and the withdrawal of Russia due to the Bolshevik Revolution shifted the balance. By 1918, the Central Powers were on the back foot, suffering from blockades, uprisings, and a lack of resources necessary to continue the war. The exhausted opposing forces began to seek an end to the conflict.

An end to the First World War became a tangible reality with the signing of the Armistice on November 11, 1918. After the Central Powers collapsed internally with uprisings and political turmoil, the leaders of the belligerent countries negotiated terms for peace. 10 days after the Armistice, the German navy surrendered.

The Armistice effectively ended hostilities and set the stage for the Treaty of Versailles, which would officially conclude the war and redraw the map of Europe. The end of World War I also set in motion a series of events that would eventually lead to the Second World War two decades later.

The human propensity for conflict traces a long and somber path through history. The early skirmishes in the fertile lands of ancient Sumer eventually gave rise to the concept of war as we came to understand it — a structured, often prolonged conflict between organized states or nations for dominance, resources, or survival. These initial sparks of conflict laid the groundwork for understanding the political and psychological underpinnings of war, a thread that runs through human history to the cataclysmic events of more recent history.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.