World War I, also known as the First World War or the Great War, was an international conflict involving much of Europe as well as distant countries from Asia, North America and the Middle East. From 1914 to 1918, the conflict continued unabated while battles decimated the European countryside and soldiers were slaughtered in unprecedented numbers.
For five bloody years, the Central Powers of Germany, Austria-Hungary and Turkey fought the Allied forces of England, France, Russia, Italy, Japan and, later, the United States. The war left an indelible mark on global geopolitical history. Following the defeat of the Central Powers in 1918, four imperial dynasties fell, Europe's society and governments were destabilized, revolutions were waged and the groundwork was laid for future international conflict.
Outbreak of War (1914-1915)
Following the Balkan Wars of 1912-13, Serbia set their sights on liberating the Slavic peoples of Austria-Hungary. The assassination of Archduke Franz Ferdinand and his wife Sophie in Sarajevo on June 28, 1914 by Bosnian Serb Gavrilo Princip served as the spark which ignited World War I. Assured of support by Germany, Austria-Hungary responded to the event by declaring war on July 23. Despite protests by allied nations France and Russia, Austria-Hungary refused Serbia's offer of international arbitration, severed its diplomatic ties with the country and began to mobilize its military forces. Following the official declaration of war on July 28, Austria-Hungary began an immediate bombardment of Belgrade.
By July 30, Russian troops began to mobilize along their border with Austria-Hungary. Germany issued ultimatums to Russia and France. Both countries refused to meet these demands. England, which had previously remained neutral, became involved in the war after Germany invaded Belgium on August 3. By the end of August, Serbia was at war with Germany; Austria-Hungary with Russia Serbia, Japan and Belgium; France, England, Russia and Montenegro with Austria-Hungary; and Montenegro and Japan with Germany.
The majority of European citizens welcomed the war with idealistic patriotism, and most expected it would be concluded over a period of months.
Early Stages of War (1914)
Germany's invasion of Belgium and France began in August 1914. Two million troops fought along the borders of France, Germany and Belgium in the Battle of the Frontiers. On September 6, the Allies launched a six-day counterattack culminating in the First Battle of the Marne, forcing a German retreat of nearly 50 miles. Meanwhile, both sides were digging trench networks westward from Aisne. Antwerp fell to the German army on October 10. By the year's end, more than 700,000 soldiers had been killed and an entrenched barrier known as the Western Front stretched from Switzerland to the Atlantic Ocean.
In the east, Russian troops crossing into East Prussia posed a major threat to the German army. They were utterly defeated by Germany during the six-day Battle of Tannenberg. Russia was finally driven out of East Prussia by September 15. Meanwhile, Austria had invaded Serbia and, despite a series of successful offensives, retreated by December 15. Turkey (then known as the Ottoman Empire) had formed an alliance with Germany against Russia, and assisted them in the war by sea and with a series of offensives in the Caucasus and the Sinai Desert.
Naval battles began on August 28, 1914. German submarines began attacking commercial traffic on October 20, and England responded with a naval blockade. Neutral nations such as the United States became increasingly hostile to Germany's policy of bombing neutral trading ships who entered its self-declared "war zone" around the British Isles. The sinking of passenger liners the Lusitania and the Arabic increased the likelihood of eventual U.S. entry into the war.
Stalemate Years (1915-1917)
By the end of 1914, it was clear that the Western Front was locked in a stalemate. Campaigns throughout February and March of 1915 resulted in massive casualties with little ground gained or lost. Other Allied offensives led to similar results. Germany began using chlorine gas on April 22, and expanded its rail system to circumvent England's naval blockade.
A Russian retreat in late April continued until October 1915, halting along a line between the Baltic Sea and the Romanian border. A Russian offensive against Turkey, launched in November 1914, had been defeated by January 1915. Turkey was expelled from neutral Persia in March. In Mesopotamia, England would continue its fruitless advance toward Baghdad. The Turkish threat diminished considerably after a 1917 revolt by Syria and Palestine. Austria's repeated attempts to invade Serbia culminated in an attack in October 1915, aided by Bulgaria. An Allied attempt to send help through Salonika merely resulted in increasing troop commitments in an area that offered little in the way of advancing the war effort.
After signing the Treaty of London April 26, 1915, Italy agreed to join the Allied cause. On May 23, they declared war on Austria-Hungary. An initial advance was followed by trench warfare, and the six Battles of the Isonzo resulted with many casualties and little advancement.
In 1916, Germany began a heavy bombardment of France, but advancement was stopped by the Somme Offensive in July-September. In summer 1916, England and Germany squared off in the Battle of Jutland, the largest naval battle in history. Along the Eastern Front, Russia launched offensives against Germany in March 1916 and came to Italy's aid in June. Brusilov's offensive would be their final military stand in World War II. An April 1917 mutiny of French soldiers greatly reduced France's military strength, while anarchy and chaos following the Russian Revolution led to a demoralization that seemed disastrous for the Allies.
After severing diplomatic ties with Germany on February 3, 1917, continued submarine attacks finally pushed the United States to declare war on April 6. Haiti, Honduras, Brazil, Guatamala, Nicaragua and Costa Rica, China and occupied Greece would do the same. These additional troops, armaments and financial resources would turn the tide of the war and eventually lead to the Allies' victory.
Success on the Italian front led Austria and Germany to launch an offensive against Italy, leading to a unified Allied military command following the Supreme War Council at Versailles. Meanwhile, England forced the Turks to retreat through Mesopotamia and occupied Jerusalem by December 9, 1917.
Under pressure from the Allies, the German submarine campaign was diminished and eventually defeated. England developed the world's first military air service, the Royal Air Force, in 1916 as a response to repeated attacks by German dirigible airships known as Zeppelins.
Emperor Francis Joseph of Austria died on November 21, 1916. Negotiation attempts by the new emperor and foreign minister began in the spring of 1917, but ultimately came to nothing. President Woodrow Wilson of the United States launched a campaign for peace with a series of pronouncements in 1918. This significantly affected the morale of the German people.
Final Offensives and Victory (1918)
After Russia's withdrawal, Germany diverted its troops from the Eastern Front. Their offensive strategy included intense artillery bombardments, followed by elite assault infantry troops. The main attack, code-named "Michael", would occur on a weak stretch of the front between Arras and La Fère. Three other supplementary attacks were to be launched against England and France: "St. George I", on the Lys River; "St. George II", between Armentières and Ypres, and "Blücher" in Champagne.
"Michael" began on March 21, 1918. Now referred to as the Second Battle of the Somme or the Battle of Saint-Quentin, it was not universally successful. St. George I" began on April 9, followed by "St. George II" on April 10. Armentières fell to the Germans, and an advance of ten miles was made before England halted the German army near Hazebrouck."Blücher" was launched by fifteen German divisions on May 27, 1918.
This offensive was considered a major tactical success, if not a strategic one, by the Germans. However, it came at a cost: the German army suffered 800,000 casualties, many of them elite soldiers. None of the advances successfully destroyed enemy railways, and the Allies continued receiving support from the United States at a rate of 300,000 new soldiers each month.
A new German attack on July 15, opening the Second Battle of the Marne, was largely unsuccessful. The Allies launched a counterstroke on July 18. British, Australian and Canadian soldiers surprised the Germans on August 8, 1918. Quartermaster General Erich Ludendorff considered this to be to be a turning point in the war, and advised Emperor William II and other political powers to open peace negotiations before the situation deteriorated further. Meanwhile, continued attacks by the Allied army drove the Germans back to their March 1918 front behind the Hindenburg line. Following the Germans retreat, the Allies began to plan a combined offensive, hoping to end the war.
End of the War (1918)
Chancellor Georg von Hertling resigned on September 29, 1918, and was replaced by Prince Maximilian of Baden on October 3. Germany sent an armistice request to the United States on October 4. With the signing of the Armistice document on November 11, 1918, World War I officially ended.
It is estimated that, in total, more than 41 million soldiers and civilians lost their life, making it one of the deadliest wars of all time.