First World War

The First World War, also known as World War I or the Great War, was a global conflict that lasted from July 28, 1914, to November 11, 1918. It involved most of the world's great powers assembled in two opposing alliances: the Allies (or Entente Powers) and the Central Powers. The war was primarily fought in Europe, but it extended to the Middle East, Africa, and parts of Asia and the Pacific Ocean. It marked the first time in history that modern industrial warfare was employed on a massive scale, resulting in unprecedented destruction and loss of life.

Causes of the First World War

The origins of the First World War were rooted in a complex web of political, economic, and social factors that had been building in Europe for decades. Key causes included militarism, where nations built up large armies and navies; alliances, such as the Triple Entente (comprising France, Russia, and the United Kingdom) and the Triple Alliance (Germany, Austria-Hungary, and Italy); imperialism, leading to rivalries over colonies; and nationalism, which fueled ethnic tensions, particularly in the Balkans.

The immediate trigger was the assassination of Archduke Franz Ferdinand of Austria-Hungary on June 28, 1914, in Sarajevo by Gavrilo Princip, a Bosnian Serb nationalist associated with the Black Hand group. This event led Austria-Hungary to issue an ultimatum to Serbia, and when Serbia did not fully comply, Austria-Hungary declared war on July 28, 1914. Alliances quickly drew in other powers: Russia mobilized to support Serbia, prompting Germany to declare war on Russia on August 1 and on France on August 3. Germany's invasion of neutral Belgium brought Britain into the war on August 4.

Major Participants

The Central Powers initially included Germany, Austria-Hungary, the Ottoman Empire (joined in 1914), and Bulgaria (joined in 1915). The Allies were led by France, the Russian Empire, and the British Empire, with later additions including Italy (switched sides in 1915), Japan, the United States (entered in 1917), and numerous other nations from Europe, Asia, Africa, and the Americas. Over 70 million military personnel were mobilized, including troops from colonies worldwide.

Key Events and Timeline

The war can be divided into several phases:

• 1914: Opening Campaigns - Germany implemented the Schlieffen Plan, invading Belgium and France. The Battle of the Marne (September 1914) halted the German advance, leading to trench warfare on the Western Front. On the Eastern Front, Russia invaded Germany but was defeated at the Battle of Tannenberg (August 1914).
• 1915: Stalemate and Expansion - The war expanded with the Gallipoli Campaign (April 1915–January 1916), an unsuccessful Allied attempt to knock Ottoman Empire out of the war. Italy joined the Allies. Naval warfare intensified, including the Battle of Jutland (May 1916).
• 1916: Year of Attrition - Major battles included the Battle of Verdun (February–December 1916) and the Battle of the Somme (July–November 1916), both on the Western Front, resulting in massive casualties. The Brusilov Offensive on the Eastern Front weakened Austria-Hungary.
• 1917: Turning Points - The Russian Revolution led to Russia's withdrawal via the Treaty of Brest-Litovsk (1918). The United States entered after Germany's unrestricted submarine warfare and the Zimmermann Telegram. The Nivelle Offensive failed, causing mutinies in the French Army.
• 1918: Endgame - Germany launched the Spring Offensive, but Allied counterattacks, bolstered by American troops, pushed back. The Hundred Days Offensive led to the collapse of the Central Powers. Armistices were signed with Bulgaria (September), the Ottoman Empire (October), Austria-Hungary (November), and Germany (November 11, 1918).

Theatres of War