Timeline of Major War Declarations in World War I

When a Yugoslav nationalist assassinated Archduke Franz Ferdinand, heir to the throne of Austria-Hungary, on June 28, 1914, many Americans had no idea Europe was at the brink of war. A flurry of diplomatic maneuvers followed in the July Crisis, and the first shots were fired July 28.

International alliances eventually drew in all the world’s economic powers either as Allies (also called Entente Powers), aligned with Russia and Serbia, or Central Powers, aligned with Austria-Hungary (see the timeline below). The United States entered the war in 1917, after attempting to remain neutral.

By the war’s official end Jan. 19, 1920, more than 70 million military personnel worldwide had been mobilized—including 4 million from the United States—and 9 million killed. Civilians were swept up, too, serving as nurses and ambulance drivers; filling vacant jobs in offices and factories; planting victory gardens and sewing bandages; and in Europe, watching their homelands be destroyed. Up to 8 million civilians died as a result of the war.

Many call the Great War the “forgotten war,” saying it’s been overshadowed by its sequel, World War II, in the American consciousness. But our ancestors who lived through it never forgot. By learning about their experiences, we can remember, too, and honor the sacrifices of service members and civilians from around the globe.

Here’s a history of WWI declarations of war, which trace how World War I began. In the text below, red indicates the Central Powers and blue indicates the Allied Powers.

1914

July 28: Austria-Hungary declares war on Serbia
Aug. 1: Germany and Russia declare war on each other
Aug. 3: Germany and France declare war on each other
Aug. 4: Germany declares war on Belgium, United Kingdom declares war on Germany
Aug. 6: Austria-Hungary declares war on Russia, Serbia declares war on Germany
Aug. 12: United Kingdom and France declare war on Austria-Hungary
Aug. 22: Austria-Hungary declares war on Belgium
Aug. 23: Japan declares war on Germany
Aug. 25: Japan declares war on Austria-Hungary
Aug. 28: Austria-Hungary declares war on Belgium
Nov. 2: Russia and Serbia declare war on the Ottoman Empire
Nov. 5: United Kingdom and France declare war on the Ottoman Empire

1915

May 23: Italy declares war on Austria-Hungary
Aug. 21: Italy declares war on the Ottoman Empire
Aug. 28: Italy declares war on Germany
Oct. 14: Bulgaria declares war on Serbia
Oct. 15: United Kingdom declares war on Bulgaria
Oct. 16: France declares war on Bulgaria
Oct. 19: Russia and Italy declare war on Bulgaria

1916

March 9: Germany declares war on Portugal
March 15: Austria-Hungary declares war on Portugal
Aug. 27: Italy declares war on Germany, Romania declares war on Austria-Hungary
Aug. 28: Germany declares war on Romania
Aug. 30: Ottoman Empire declares war on Romania
Sept. 1: Bulgaria declares war on Romania

1917

April 6: United States declares war on Germany
June 27: Greece declares war on Austria-Hungary, Bulgaria, Germany and the Ottoman Empire
Aug. 14: China declares war on Germany
Dec. 7: United States declares war on Austria-Hungary

Adapted from the July/August 2014 issue of Family Tree Magazine.

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