Florida Memory Timeline Challenge banner image with vertical American flag background and smaller images in a line, including a map of Florida, Mary McLeod Bethune, people celebrating V-J Day, Betty Mae Tiger Jumper, and the Challenger space shuttle launch.

World War I

World War I began on July 28, 1914, after Austria-Hungary declared war on Serbia following the assassination of Archduke Franz Ferdinand of Austria by a Bosnian Serb. The United States declared war on the German Empire on April 6, 1917, in response to attacks on American ships by German U-boats and the discovery of a secret offer from Germany to Mexico to help them take back land in the Southwestern United States that Mexico had lost during the Mexican-American War almost 70 years earlier. This marked America's entry into World War I.

It was the first conflict to include fighting across multiple continents, at sea and in the air. At the time, it was called the Great War, and some people were so stunned by the size and scope that they called it "the war to end all wars." Unfortunately, when World War I ended there were many unresolved issues and tensions between nations that only built as the years went by.

Frontpage of an Italian newspaper with a color drawing depicting the assassination of Archduke Franz Ferdinand and Duchess Sophie.
Achille Beltrame, Assassination of Franz Ferdinand, 1863-1914 Archduke of Austria, and his wife Sophie, in Sarajevo, Bosnia, 28 June 1914, [12 July 1914], Wikimedia Commons, Public Domain, DC-1914-27-d-Sarajevo.
June 28, 1914
Assassination of Archduke Franz Ferdinand and Duchess Sophie

On June 28, 1914, Archduke Franz Ferdinand, heir of the Austro-Hungarian Empire, and his wife Sophie, Duchess of Hohenberg, were assassinated by a secret group of Serbian nationalists called the Black Hand. When Austria-Hungary declared war on Serbia a month later, alliances between European powers drove other nations to declare their loyalties to either Serbia or Austria-Hungary.

Learn More

Frontpage of an American newspaper with a heading Neutrality is Declared by President Wilson World's Greatest War.
[Frontpage of The Anderson Daily Intelligencer], 5 August 1914, Library of Congress, Chronicling America, sn93067669.
August 4, 1914
President Wilson Declares American Neutrality in War

As war began in Europe, President Woodrow Wilson declared on August 4, 1914, that the United States would remain neutral. At the time, many Americans supported the president's decision, but attitudes began to shift as the war progressed.

Learn More

  • "Arguing Over War," in Echoes of the Great War: American Experiences of World War I (Library of Congress, n.d.).

Dry plate negative of the RMS Lusitania, a British luxury ocean liner.
Detroit Publishing Co., The Lusitania, c1907, Library of Congress, Detroit Publishing Company Photograph Collection, 2016806378.
May 7, 1915
The Sinking of the Lusitania

On May 7, 1915, a German U-boat sank the RMS Lusitania, a British ocean liner, off the coast of Ireland. Over 1,000 people died, including 100 U.S. citizens, while 767 escaped in lifeboats. The loss of American life increased the American public's support for joining the war.

Learn More

A group of people on the deck of the French passenger ferry the SS Sussex after being torpedoed by a German U-boat in the English Channel during World War I.
On Sussex After Explosion, [1916], Library of Congress, Bain News Service Photograph Collection, 2014701801.
May 4, 1916
Germany Issues the Sussex Pledge

After a German submarine torpedoed the SS Sussex, a French passenger ferry, on March 24, 1916, the German government promised to stop attacking nonmilitary ships and issued the Sussex Pledge on May 4, 1916. The attack on the SS Sussex killed 50 people and injured hundreds, including several Americans. President Woodrow Wilson warned that continued attacks on civilians would force the United States to declare war on Germany.

Learn More

  • Simone De Santiago Ramos, "Sussex Pledge," in 1914-1918-Online. International Encyclopedia of the First World War (Freie Universität Berlin, 2015)

A British tank in the Somme, France, during World War I.
British Tank, 25 September 1916, Library of Congress, George Grantham Bain Collection, 2014705407.
September 15, 1916
First Use of Tanks in Combat

On September 15, 1916, the British Army used tanks on the battlefield for the first time at the Battle of Flers-Courcelette. Most of the tanks got stuck, broke down, or were destroyed by enemy fire. Improvements on the new technology turned tanks into a key tool in mobile warfare, helping ground troops move more quickly instead of waiting in trenches.

Learn More

Political cartoon depicting a hand in a gauntlet decorated with the imperial German eagle carving up a map of the Southwestern United States.
Clifford Kennedy Berryman, [Hand Carving Up a Map of the Southwestern United States], 4 March 1917, Library of Congress, Cartoon Drawings, 2016678747.
January 17, 1917
Britain Intercepts the Zimmerman Telegram

The Zimmerman telegram or note was a coded message sent from German Foreign Secretary Arthur Zimmermann to the German ambassador to Mexico proposing an alliance against the United States.

Learn More

President Woodrow Wilson speaking before a joint session of Congress.
Harris & Ewing, President Wilson Before Congress, Announcing the Break in the Official Relations With Germany, 3 February 1917, National Archives at College Park, 533722.
April 6, 1917
United States Joins World War I

On April 4, 1917, the United States Senate voted to declare war on the German Empire, and the U.S. House of Representatives followed suit two days later. With Congress and President Woodrow Wilson in agreement, the U.S. formally entered World War I on April 6, 1917. Although the American public had been overwhelmingly in favor of remaining neutral, Germany's continued attacks against U.S. ships had changed public opinion.

Learn More

A crowd of men in suits lined up in the street as several onlookers watch out of the windows of buildings in the background.
Burgert Brothers, Draftees Assembled During World War I - Tampa, Florida, 1917, Florida Memory, Reference Collection, RC21497.
May 18, 1917
65th Congress Passes the Selective Service Act

The Selective Service Act temporarily gave the federal government the power to expand the U.S. military through conscription, also called a draft. Of all the U.S. troops sent to Europe during World War I, more than half (2.8 million) had been drafted.

Learn More

Drawing of an arm labeled espionage bill grabbing the torch from the Statue of Liberty's hand.
Winsor McCay, Must Liberty's Light Go Out?, 3 May 1917, Library of Congress, 96519622.
June 15, 1917
65th United States Congress Passes the Espionage Act

On June 15, 1917, the 65th United States Congress passed the Espionage Act. Under the act, espionage (or spying) included any activity that could threaten the country's military operations, including recruitment, or anything that could help an enemy nation. The act put new limits on Americans' First Amendment rights.

Learn More

General Pershing and members of the American Expeditionary Forces walking.
Harris & Ewing, First Division, A.E.F. American Expeditionary Forces. General Pershing, 1919, Library of Congress, Harris & Ewing Photograph Collection, 2016870460.
July 5, 1917
Creation of the American Expeditionary Forces

When the United States declared war on Germany on April 6, 1917, the country had under 130,000 soldiers and officers in its army. The American Expeditionary Forces were established on July 5, 1917, to fight on the Western Front.

Learn More

President Wilson addressing Congress on his Fourteen Points plan.
Wilson Addressing Congress on the Fourteen Points, 8 January [1919], Wikimedia Commons, Woodrow Wilson Presidential Library Archives, 4435105235.
January 8, 1918
President Wilson Introduces His Fourteen Points to Congress

During a speech to Congress on January 8, 1918, President Woodrow Wilson outlined his Fourteen Points. Some of the key points focused on getting rid of secret treaties between nations, reducing the armaments (the military weapons and equipment) each nation had, allowing for free trade, and creating the League of Nations.

Learn More

Men from the 369th Infantry Regiment returning from France.
International Film Service, Colored Troops - New York's Colored Regiment Returns Home on Stockholm, 12 February 1919, National Archives at College Park, American Unofficial Collection of World War I Photographs, 26431282.
April 8, 1918
Harlem Hellfighters Join the French Army on the Front Lines

The 369th Infantry Regiment, or the Harlem Hellfighters, was an African American regiment that became one of the first American regiments in World War I. On April 8, 1918, they were assigned to serve with the French Army and would later earn the Croix de Guerre, France's highest military honor, for their bravery. Despite this, they faced racism and discrimination both during and after the war.

Learn More

American soldiers with a Howitzer in Belleau Woods.
Belleau Woods. American Howitzer - Picking a Spot for American Shells to Fall, 1926, Library of Congress, 2023638420.
June 6, 1918
Allies Attack German Forces at the Battle of Belleau Wood

On June 6, 1918, the Allies moved to drive the German forces out of Belleau Wood and stop them from getting closer to Paris. Both the U.S. Army and Marines fought at Belleau Wood alongside troops from the French and British armies. The Allies won after three weeks of fighting.

Learn More