Humanities › History & Culture World War I Timeline From 1914 to 1919 Share Flipboard Email Print History & Culture Military History World War I Battles & Wars Key Figures Arms & Weapons Naval Battles & Warships Aerial Battles & Aircraft Civil War French Revolution Vietnam War World War II American History African American History African History Ancient History and Culture Asian History European History Genealogy Inventions Latin American History Medieval & Renaissance History The 20th Century Women's History View More By Jennifer Rosenberg History Expert B.A., History, University of California at Davis Jennifer Rosenberg is a historian and writer who specializes in 20th-century history. our editorial process Jennifer Rosenberg Updated August 21, 2019 World War I was sparked by the assassination of Archduke Franz Ferdinand in 1914 and ended with the Treaty of Versailles in 1919. Find out what happened in between these momentous events in this World War I timeline. 01 of 06 1914 De Agostini/Biblioteca Ambrosiana/Getty Images Although World War I officially began in 1914, much of Europe had been roiled by political and ethnic conflict for years before. A series of alliances among the leading nations committed them to each other's defense. Meanwhile, regional powers like Austria-Hungary and the Ottoman Empire were teetering on the brink of collapse. Against this backdrop, Archduke Franz Ferdinand, heir to Austria-Hungary's throne, and his wife, Sophie, were assassinated by Serbian nationalist Gavrilo Princip on June 28 while the couple was visiting Sarajevo. That same day, Austria-Hungary declared war on Serbia. By Aug. 6, the British Empire, France, and Russia were at war with Serbia and Germany. U.S. President Woodrow Wilson announced the U.S. would remain neutral. Germany invaded Belgium on Aug. 4 with the intent of attacking France. They made swift progress until the first week of September when the German advance was stopped by French and British troops at the First Battle of the Marne. Both sides began digging in and fortifying their positions, signaling the start of trench warfare. Despite the slaughter, a one-day Christmas truce was declared on Dec. 24. 02 of 06 1915 Print Collector/Getty Images/Getty Images In response to a North Sea military blockade that Britain imposed the previous November, on Feb 4. Germany declared a war zone in the waters around the U.K., beginning a campaign of submarine warfare. This would lead to the May 7 sinking of the British ocean liner Lusitania by a German U-boat. Stymied in Europe, Allied forces tried to gain momentum by attacking the Ottoman Empire twice where the Sea of Marmara meets the Aegean Sea. Both the Dardanelles Campaign in February and the Battle of Gallipoli in April proved costly failures. On April 22, the Second Battle of Ypres began. It is during this battle that the Germans first used poison gas. Soon, both sides were engaged in chemical warfare, using chlorine, mustard, and phosgene gasses that injured more than 1 million men by war's end. Russia, meanwhile, was fighting not just on the battlefield but at home as the government of Tsar Nicholas II faced the threat of internal revolution. That fall, the tsar would take personal control over Russia's army in a last-ditch attempt to shore up his military and domestic power. 03 of 06 1916 Heritage Images/Getty Images By 1916, the two sides were largely stalemated, fortified in mile after mile of trenches. On Feb. 21, German troops launched an offensive that would become the longest and bloodiest of the war. The Battle of Verdun would drag on until December with little in the way of territorial gains on either side. Between 700,000 and 900,000 men died on both sides. Undeterred, British and French troops launched their own offensive in July at the Battle of the Somme. Like Verdun, it would prove a costly campaign for all involved. On July 1 alone, the first day of the campaign, the British lost more than 50,000 troops. In another military first, the Somme conflict also saw the first use of armored tanks in battle. At sea, the German and British navies met in the first and largest naval battle of the war on May 31. The two sides fought to a draw, with Britain enduring the most casualties. 04 of 06 1917 Heritage Images/Getty Images Although the U.S. was still officially neutral at the start of 1917, that would soon change. In late January, British intelligence officers intercepted the Zimmerman Telegram, a German communique to Mexican officials. In the telegram, Germany tried to entice Mexico into attacking the U.S., offering Texas and other states in return. When the contents of the telegram were revealed, U.S. President Woodrow Wilson broke off diplomatic relations with Germany in early February. On April 6, at Wilson's urging, Congress declared war on Germany, and the U.S. officially entered World War I. On Dec. 7, Congress would also declare war against Austria-Hungary. However, it wouldn't be until the following year that U.S. troops began arriving in numbers large enough to make a difference in the battle. In Russia, roiled by domestic revolution, Tsar Nicholas II abdicated on March 15. He and his family would eventually be arrested, detained, and murdered by revolutionaries. That fall, on Nov. 7, the Bolsheviks successfully overthrew the Russian government and quickly withdrew from World War I hostilities. 05 of 06 1918 Heritage Images/Getty Images The United States' entry into World War I proved to be the turning point in 1918. But the first few months didn't seem so promising for Allied troops. With the withdrawal of Russian forces, Germany was able to reinforce the western front and launch an offensive in mid-March. This final German assault would reach its zenith with the Second Battle of the Marne on July 15. Although they inflicted substantial casualties, the Germans could not muster the strength to combat the reinforced Allied troops. A counteroffensive led by the U.S. in August would spell the end of Germany. By November, with morale at home collapsing and troops in retreat, Germany collapsed. On Nov. 9, German Kaiser Wilhelm II abdicated and fled the country. Two days later, Germany signed the armistice at Compiegne, France. Fighting ended on the 11th hour of the 11th day of the 11th month. In later years, the date would be commemorated in the U.S. first as Armistice Day, and later as Veterans Day. All told, some 11 million military personnel and 7 million civilians died in the conflict. 06 of 06 Aftermath: 1919 Bettmann Archive/Getty Images Following the conclusion of hostilities, the warring factions met at the Palace of Versailles near Paris in 1919 to formally end the war. A confirmed isolationist at the beginning of the war, President Woodrow Wilson had by now become an ardent champion of internationalism. Guided by his 14 Points statement issued the previous year, Wilson and his allies sought a lasting peace enforced by what he called the League of Nations, a forerunner to the United Nations of today. He made the league's establishment a priority of the Paris Peace Conference. The Treaty of Versailles, signed on July 25, 1919, imposed strict penalties on Germany and forced it to accept full responsibility for the starting the war. The nation was not only forced to demilitarize but also cede territory to France and Poland and pay billions in reparations. Similar penalties were also imposed on Austria-Hungary in separate negotiations. Ironically, the U.S. was not a member of the League of Nations; participation was rejected by the Senate. Instead, the U.S. embraced a policy of isolationism that would dominate foreign policy in the 1920s. The harsh penalties imposed on Germany, meanwhile, would later give rise to radical political movements in that nation, including Adolf Hitler's Nazi Party.