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The Assassination of Archduke Franz Ferdinand and His Wife, Sophie
While on a trip to Bosnia's capital, Sarajevo, Archduke Franz Ferdinand and his wife, Sophie were killed by a member of the Black Hand - a secret Serbian nationalist society that wanted to rid Serbia of Austro-Hungarian rule. Angered by the assassination of their heir to the throne, Austria-Hungary proposed an ultimatum to Serbia. After Serbia refused to accept all the terms, Austria-Hungary declared war on July 28, 1914. -
Germany's Blank Check to Austria-Hungary
After the assassination of Archduke Ferdinand, Germany's Kaiser Wilhelm II promised to support Austria-Hungary, "even if it meant war with Russia" (Countdown to WWI). This "blank check" assurance gave Austria-Hungary the confidence to later declare war with Serbia. -
WWI Begins - Austria-Hungary Declares War with Serbia
Exactly one month after the Archduke Ferdinand's assassination, Austria-Hungary declared war with Serbia. As Serbia's ally, Russia began to prepare for war and moved troops into the Balkans. -
Germany Declares War With Russia
When Russia refused to demobilize their troops, Germany declared war. This began the domino effect of European powers being drawn into war. -
Germany Declares War With France
Knowing that they would be fighting a war on two fronts if they didn't take quick action to defeat France, Germany declared war. To gain access to France, they invaded the neutral country of Belgium, prompting Great Britain to defend their ally. -
Great Britain Declares War With Germany
To protect their Belgian ally, Great Britain gave Germany an ultimatum to either leave Belgium or go to war. When Germany refused, Britain declared war. Europe was then involved in a full-scale world war. -
Germany Sinks the USS Lusitania
In response to Britain's blockade, German U-boats began attacking ships carrying contraband. The Lusitania was torpedoed, despite being a passenger ship. Almost 2,000 people died, including 124 Americans (Interactive WWI Timeline). The United States was infuriated that yet another an unarmed ship was attacked and that Germany had violated international law in doing so. President Woodrow Wilson sent several letters to Germany, imploring them to cease unrestricted submarine warfare. -
Germany Declares Unrestricted Submarine Warfare
Despite the known risk of provoking the United States to finally enter World War I, Germany began unrestricted submarine warfare at the beginning of 1917. After nearly two years of German U-boats sinking neutral merchant ships and repeatedly breaking promises to stop their surprise attacks, President Wilson "broke off diplomatic relations with Germany" to try and reverse their decision (Unrestricted Submarine Warfare). However, Germany continued, prompting the U.S. to join the war in April. -
The Zimmerman Telegram Is Intercepted
British forces intercepted a telegram from Germany's Foreign Minister Andrew Zimmerman to Mexico in January 1917. In the message, Germany tells Mexico that they will help reclaim land lost to the United States if Mexico sides with Germany in the war. Britain turned the decoded telegram over to President Woodrow Wilson on the 24th of February. (The Zimmerman Telegram) This infuriated and terrified the United States and provoked them to join World War I about one month later. -
The US Enters the War
After receiving the Zimmerman telegram in February and the resumption of unrestricted submarine warfare, President Wilson could no longer keep the United States neutral in the war. The U.S. joined the Allies on the Western Front, where they had been battling through trench warfare and were in stalemate. Germany had large numbers of troops returning from the Eastern Front, but the fresh American troops helped push back their advance and eventually win the war (America in the First World War). -
The War Ends - Its Effects
There were nearly 37 million total casualties throughout the course of WWI. European countries were destroyed and in great debt, causing an enormous amount of inflation. Despite all of this, the US economy was flourishing, though it would soon give way to the Great Depression. The war also created a worldwide sense of disillusionment. This distrust of government led to many countries establishing new forms of government and trying to recover from the war's devastating effects (Effects of WWI). -
The Treaty of Versailles Is Signed
The Allied Powers gathered in Versailles to negotiate a peace treaty after Germany signed an armistice on November 11, 1918. The treaty forced Germany to give up territories, significantly decrease the size of their military, and pay reparations for damage caused during the war. Most significant of all was that Germany was made to take full responsibility for WWI. This "War Guilt Clause" humiliated the Germans and made them resent the Allies, leading to the rise of Hitler and eventually WWII.