The following tables list the main events which happened during World War I.

Western Theater Eastern Theater Italian Theater
Caucasian Theater Middle East Theater Balkan Theater
Colonial Theater Naval Theater Diplomacy and politics


Dates Events
June 28 Assassination of Archduke Franz Ferdinand of Austria, heir to the Austro-Hungarian throne, who is killed in Sarajevo along with his wife, Duchess Sophie. Details
July 23 Austria-Hungary sends an ultimatum to Serbia. The Serbian response is seen as unsatisfactory. Details
July 28 Austria-Hungary declares war on Serbia. Russia mobilizes. The Great War begins.
July 31 Germany enjoins Russia to stop mobilizing. Russia says mobilization is against Austria-Hungary only.
August 1 Germany declares war on France.
Italy declares its neutrality.
Germany and the Ottoman Empire sign a secret alliance treaty.
August 2 Germany invades Luxembourg. Details
August 4 Germany invades Belgium[1] to outflank the French army. Details
Britain protests the violation of Belgian neutrality, guaranteed by a treaty;
German Chancellor replies that the treaty is just a chiffon de papier (a scrap of paper).
The United Kingdom declares war on Germany.
August 5 Montenegro declares war on Austria-Hungary.
The Ottoman Empire closes the Dardanelles.
August 5–August 16 The Germans besiege and then capture the fortresses of Liège, Belgium. Details
August 6 Austria-Hungary declares war on Russia.
Serbia declares war on Germany.
August 7 The British Expeditionary Force arrives in France. Details
August 9 Montenegro declares war on Germany.
August 11 France declares war on Austria-Hungary.
August 12 The United Kingdom declares war on Austria-Hungary.
August 14–August 24 Battle of the Frontiers. The Germans obtain a victory against the British Expeditionary Force and France's Fifth Army. Details
August 16–August 19 The Serbs defeat the Austro-Hungarians at the Battle of Cer. Details
August 17 The Russian army enters East Prussia. Battle of Stalluponen. Details
August 20 The Germans attack the Russians in East Prussia. The attack is a failure in addition to being a violation of the Schlieffen Plan. Details
August 17–September 2 Battle of Tannenberg: the Russian army undergoes a heavy defeat by the Germans. Details
August 20 The Germans occupy Brussels.
August 22 Austria-Hungary declares war on Belgium.
August 23 Japan declares war on Germany.
August 23–August 25 Battle of Kraśnik. The Austro-Hungarian First Army defeats the Russian Fourth Army Details
August 24–September 7 The Germans siege and capture the Maubeuge Fortress. Details
August 25 Japan declares war on Austria-Hungary.
August 26 British and French forces invade Togoland, a German protectorate in West Africa. Details
August 26–August 27 Battle of Le Cateau. Allied retreat. Details
August 26–September 11 Battle of Lemberg. The Russians capture Lviv. Details
August 27–November 7 Battle of Tsingtao: British and Japanese forces capture the German-controlled port of Tsingtao in China. Details
August 28 The Royal Navy wins the First Battle of Heligoland Bight, North Sea. Details
August 29–August 30 Battle of Saint Quentin, aka Battle of Guise. Orderly Allied retreat. Details
August 30 New Zealand occupies German Samoa (later Western Samoa). Details
September 3–September 11 Austro-Hungarian defeat at the Battle of Rava Russka. Details
September 5–September 12 First Battle of the Marne. The German advance on Paris is halted, marking the failure of the Schlieffen Plan. Details
September 7–September 14 First Battle of the Masurian Lakes: The Russian Army of the Neman withdraws from East Prussia with heavy casualties. Details
September 8–September 17 Second Austro-Hungarian attempt at invading Serbia fails.
September 9 Theobald von Bethmann Hollweg lays out Germany's war aims. Details
September 11–September 21 Australian forces occupy German New Guinea. Details
September 13 Troops from South Africa begin invading German South-West Africa. Details
September 13–September 28 The First Battle of the Aisne ends in a substantial draw. The Race to the Sea begins. Details
September 14 Erich von Falkenhayn replaces Helmuth von Moltke the Younger as German Chief of Staff. Details
September 17 The Siege of Przemyśl begins Details
September 28–October 10 The Germans siege and capture Antwerp, Belgium. Details
September 29–October 31 Battle of the Vistula, aka Battle of Warsaw. Details
October 16–October 31 Battle of the Yser. French and Belgian forces secure the coastline of Belgium. Details
October 19–November 22 The First Battle of Ypres ends the Race to the Sea. The Germans are prevented from reaching Calais and Dunkirk. Details
November 1 Russia declares war on the Ottoman Empire.
Battle of Coronel. Von Spee's German cruiser squadron defeats a Royal Navy squadron under Christopher Cradock. Details
November 2 The United Kingdom begins the naval blockade of Germany. Details
November 3 Montenegro declares war on the Ottoman Empire.
November 3–November 5 Von Lettow-Vorbeck's German colonial forces defeat the British at the Battle of Tanga, German East Africa. Details
November 5 France and the United Kingdom declare war on the Ottoman Empire.
November 6 The Austro-Hungarians enter Belgrade.
November 9 Battle of Cocos, northeast Indian Ocean. The Australian cruiser Sydney destroys the German cruiser Emden. Details
November 11–December 6 Battle of Łódź Details
November 11 Sultan Mehmed V declares Jihad on the Allies.
December 8 Battle of the Falklands. Von Spee's German cruiser squadron is defeated by the Royal Navy.| Details
December 16 The German fleet shells Scarborough and Hartlepool, England. Details
December 24-December 25 An unofficial Christmas truce is declared between large numbers of German and French forces. Details
December 29–January 2, 1915 The Russians win the Battle of Sarikamis, Caucasia. Details

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