June 28 - Assassination of Archduke Franz Ferdinand and his wife at Sarajevo.
July 5/6 - Germany gives Austria-Hungary blank cheque of support against Serbia.
July 23 - Austro-Hungarian ultimatum to Serbia.
July 25 - Serbia mobilises.
July 26 - Austro-Hungarian mobilisation against Serbia; Russia enters 'period preparatory to war'.
July 28 - Franz Joseph signs declaration of war against Serbia.
July 29 - Germany demands immediate cessation of Russian mobilisation preparations.
July 30 - Russia decrees full mobilisation in support of Serbia.
July 31 - Russian mobilisation begins; Germany proclaims 'threatening danger of war' and issues ultimatum to Russia.
August 1 - Germany declares war on Russia and orders general mobilisation; France orders general mobilisation.
August 2 - German ultimatum to Belgium demanding right of passage through her territory; German troops invade Luxembourg.
August 3 - Germany declares war on France; Austria-Hungary declares war on Russia; France asks Russia to attack Germany; Turkey declares 'armed neutrality'.
August 4 - Britain declares war on Germany; Germany invades Belgium.
August 5 - Austria declares war on Russia; Montenegro declares war on Austria.
August 6 - Serbia declares war on Germany; French troops move into Upper Alsace.
August 7 - Germans captured citadel at Liege.
August 10 - France declares war on Austria-Hungary.
August 12 - Austrians invade Serbia; Britain declares war on Austria-Hungary.
August 12-13 - Russia invades East Prussia.
August 14 - Battle of the Frontiers begins.
August 17 - Battle of Gumbinnen.
August 20 - Battle of Stallupoenen.
August 23 - Battle of Mons; British Expeditionary Force begins retreat.
August 25-27 - Battle of Komarow.
August 26 - Battle of Le Cateau.
August 27-31 - Battle of Tannenberg.
August 31 - Greece formally declares neutrality.
September 3 - Battle of Lemberg.
September 5-10 - Battle of the Marne.
September 7-17 - Battle of the Masurian Lakes.
September 11 - Battle of Grodek.
September 13-27 - Battle of the Aisne.
September 14 - Falkenhayn takes over control of German operations from Moltke.
September 15 - 'Race to the Sea' begins.
October 1 - Turkey closes Dardanelles.
October 10 - Antwerp falls to the Germans.
October 18-30 - Battle of the Yser.
Oct. 19 - Nov. 22 - First Battle of Ypres.
October 19-30 - First Battle of Warsaw.
November 1 - Turkey declares war on Anglo-French entente.
November 2 - Russia and Serbia declare war on Turkey.
November 3 - Falkenhayn succeeds Moltke as Chief of the German General Staff.
November 5 - Britain and France declare war on Turkey.
November 7-17 - Second Battle of Warsaw
November 11 - Ottoman Sultan, as Caliph of Islam, proclaims jihad against Britain and France.
November 11-12 - Battle of Wloclawek.
November 13-16 - Battle of Kutno.
November 19-25 - Battle of Lodz.
December 6-12 - Battle of Limanowa-Lapanow.
December 8 - Austrian Third Army retakes Carpathian passes.
December 17 - French winter offensive begins in Artois.
December 20 - French winter offensive begins in Champagne.
December 30 - Battle of Sarikamis begins; Russia appeals to London for a diversionary attacks to be made against Turkey.
January 4 - French offensive in Artois ends.
January 17 - Russians finish mopping up operations at Sarikamis.
February 3 - Turks fail to cross Suez Canal.
February 19 - Allied fleet begins bombardment of outer forts at the Dardanelles.
March 10-12 - Battle of Neuve Chapelle.
March 18 - Anglo-French naval attack on the Chanak Narrows repulsed with loss of three battleships.
March 22 - Russians capture Przemysl, taking 100,000 prisoners.
April 22 - Germans use poison gas for the first time on the Western Front.
April 22-May 25 - Second Battle of Ypres.
April 25 - Anglo-French forces go ashore at Helles and at Kum Kale on Asiatic shore.
May 2-10 - Battle of Gorlice-Tarnow.
May 9-10 - Battle of Sanok.
May 9 - Allied offensive begins in Artois; Battle of Aubers Ridge.
May 13-18 - Battle of Jaroslaw.
May 15-27 - Battle of Festubert.
May 20-22 - Austrians retake Lemberg.
May 23 - Italian Government declares war on Austria.
May 25-26 - Formation of a Coalition Cabinet and creation of Ministry of Munitions announced in Britain.
July - Russians withdraw from Galicia.
August 4 - Allied reconnaissance party arrives at Salonika to assess port and railway facilities.
August 5 - Third Battle of Warsaw; Germans take Warsaw.
August 6 - Start of great Allied attack at Gallipoli; further landings made at Suvla Bay after dark.
August 7 - Tsar appoints himself Commander-in-Chief.
August 10 - Turkish counter-attack at Gallipoli drivres British and New Zealanders off high ground.
August 20 - Italy declares war on Turkey.
September - Zimmerwald conference of Socialist Internationals; Germans capture Vilnius.
September 21 - Greek premier Venizelos calls for massive Allied reinforcement of Salonika as condition for Greek entry into war.
September 25 - Allied offensive in Artois and Champagne; first use of poison gas by British at Battle of Loos.
September 27 - Greek King Constantine consents to Allied force landing at Salonika.
October - Battle of Dunaburg.
October 1 - British advance party arrives at Salonika.
October 5 - Combined German-Austrian attack on Belgrade begins; British and French forces land at Salonika.
October 9 - Belgrade falls; Austrians invade Montenegro.
October 11 - Bulgarian troops invade Serbia.
October 14 - Mutual declaration of war between Serbia and Bulgaria.
December 12 - Allied navies begin evacuation of Serb army from Albania.
December 19 - Evacuation of the Anzac and Suvla beach heads at Gallipoli in one night without casualties; Haig replaces Sir John French as Commander-in-Chief of the British Expeditionary Force.
January 8 - Successful completion of Gallipoli evacuation at Helles.
January 10 - Completion of Allied 'Entrenched Camp' at Salonika.
January 17 - Battle of Koprukoy; Russians advance on Erzerum.
January 27 - First Military Service Act becomes law in Britain, introducing conscription for men aged between 18 and 41.
February 7 - Russians take Hinis.
February 11-16 - Battle of Erzerum; Russians take Erzerum and Mus.
February 21 - Battle of Verdun begins.
February 25 - Germans capture Fort Douaumont at Verdun.
March 18 - Unsuccessful Russian Vilnius offensive begins; ends April 14.
April - Kienthal Conference of International Socialist.
April 24 - Easter Rising in Dublin.
April 29 - Mesopotamia: Fall of Kut with 13,309 British and Indian prisoners plus over 3,000 non-combatants.
May 25 - Second Military Service Act becomes law in British, extending the conscription to married men.
May 31-June 1 - Naval battle of Jutland.
June 4 - Opening of Brusilov's offensive.
June 5 - Arabia: Sherif Hussein starts Arab revolt at Medina, proclaims independence of Hedjaz.
July 1 - Battle of the Somme begins.
July 3-9 - Unsuccessful offensive by Russian West Front.
July 7 - Lloyd George succeeds Kitchener (drowned en route to Russia) as War Minister.
July 28 - Opening of second phase of Brusilov's offensive.
August 27 - Romania declares war on Austria-Hungary, invades Transylvania.
August 29 - Hindenburg succeeds Falkenhayn as Chief of German General Staff, with Ludendorff as 'First Quartermaster General'.
September 1 - Britain and France secretly sign the Sykes-Picot agreement on post-war partition of the Ottoman Empire.
September 6 - Romanians complete occupation of Transylvania.
September 15 - British use tanks for the first time at Flers-Courcelette on the Somme.
September 19 - German-led forces invade Transylvania.
October 3 - German victories in Transylvania and Dobrudja.
October 10 - Tsar terminates Brusilov's offensive.
October 11 - Allies disarm Greek fleet; riots in Athens in protest at Allied action.
October 16-17 - Final unsuccessful Russian effort to take Vladmir-Volynski.
October 24 - French counter-attack at Verdun; Fort Douaumont recaptured.
November 21 - Emperor Franz Joseph dies, aged 86; succeeded by his great-nephew Karl.
November 23 - Greek provisional government at Salonika declares war on Germany and Bulgaria.
November 25 - Battle of the Somme ends.
December 1 - Fighting in Athens between royalist troops and Anglo-French detachments.
December 7 - Lloyd George becomes Prime Minister, succeeds Asquith.
December 12 - Nivelle replaces Joffre as French Commander-in-Chief.
January 5-7 - Allied conference in Rome to discuss priorities for campaigns in Italy and Salonika.
February - Cold weather disrupts food and fuel supplies to Russian cities.
February 1 - Germany begins unrestricted submarine warfare.
February 18-22 - German forces commence preliminary withdrawal from Ancre sector.
February 20 - First attack on Hedjaz railway by Arab irregulars.
March 8-12 - Food riots in Petrograd; garrison troops mutiny.
March 11 - Baghdad falls to General Maude.
March 12 - Russian Revolution begins; Provisional Government and Petrograd Soviet formed.
March 14 - Petrograd Soviet Order No. 1 claims control over garrison.
March 15 - Tsar abdicates.
March 16 - Germans begin main withdrawal to the Hindenburg Line.
March 21 - Tsar and family arrested.
March 26 - First battle of Gaza.
April 6 - United States declares war on Germany.
April 9 - Opening of British Arras offensive; Canadians storm Vimy Ridge.
April 16 - Lenin arrives in Petrograd; French spring offensive begins on the Aisne.
April 17 - Second battle of Gaza; despite use of tanks, momentum is lost and attack stalls.
May 5 - Allies launch major offensive in Serbia but failt to get Serb co-operation.
May 15 - Petain succeeds Nivelle as French Commander-in-Chief.
May 16 - Kerensky becomes Russian Minister of War.
May 22 - Kerensky appoints Brusilov Commander-in-Chief.
June 7 - British attack on Messines Ridge.
June 12 - King Constantine of Greece abdicates after Allied ultimatum, succeeded by younger son Alexander; British and French troops arrive at Piraeus.
June 18 - Russian South-West Front offensive begins.
June 26 - Venizelos confirmed by allies as Greek Prime Minister.
July 2 - Russian South-West Front offensive stalls; Greece declares war on Central Powers; in Arabia, Colonel Lawrence and Arab irregulars attack Hedjaz railway and Turkish garrisons.
July 8 - Central Powers counter-attack; South-West Front retires to river Seret.
July 10 - North and West Front troops refuse to attack.
July 13 - Kornilov replaces Brusilov, calls off offensives.
July 31 - Third Battle of Ypres begins.
August 27 - Failure of Kornilov's attempt to seize power.
September 1-5 - German Riga campaign.
September 12 - Italy: New German 14th Army under General von Below deploys on Isonzo front.
October 24 - Battle of Caporetto; Austro-German attack breaks Italian 2nd Army.
October 29 - General Cadorno orders retreat to line of river Piave.
October 31 - Italians back begind river Tagliamento; in Palestine, Allenby opens third battle of Gaza.
November 5 - Allies confer at Rapallo as Italians ask for 15 Allied divisions.
November 6 - Passchendale captured by Canadians.
November 7 - Bolsheviks seize power.
November 8 - Lenin proposes peace: 'no annexation and no indemnities'.
November 9 - General Diaz replaces Cadorna as Italian Commander-in-Chief.
November 14 - Allenby resumes advance on Jerusalem.
November 16 - Clemenceau becomes French Prime Minister.
November 20 - Battle of Cambrai begins.
December 9 - Jerusalem falls to Allenby.
December 10 - Armistice between Romania and Central Powers.
December 17 - Armistice between Russia and Central Powers.
December 22 - Russo-German peace negotiations begin at Brest-Litovsk; in Salonika, General Guillaumat replaces Sarrail as Allied Commander-in-Chief; Austrians fail to break through river Piave as astonishing revival in Italian national morale takes place.
February 1 - Austrian navy mutinies at Cattaro.
February 9 - Germans sign separate peace with Ukraine.
February 16 - Trotsky ends negotiations, declares 'Neither war nor peace'.
February 19 - Germans advance to within 80 miles of Petrograd.
March 3 - Treaty of Brest-Litovsk; Russia leaves the war.
March 21 - German operation Michael offensive begins in Picardy.
March 26 - Foch appointed to co-ordinate Allied operations on Western Front.
April 9 - German Georgette offensive begins in Flanders.
May 27 - German Blucher offensive begins on the Aisne.
June 9 - Start of German Gneisenau offensive.
July 15 - Last German offensive begins near Rheims.
July 18 - Allied counterstroke on the Marne.
August 8 - Battle of Amiens begins.
September 14 - Final Allied offensive starts in Macedonia with battle of the river Vardar; mutinies break out in the Bulgarian Army.
September 19 - Allenby fights and wins battle of Megiddo; RAF aircraft destroy the Turkish 7th Army in defiles of Wadi Far.
September 23 - British capture Acre and Haifa.
September 26 - Start of Franco-American offensive in Meuse-Argonne sector; Bulgaria seeks peace terms as mutinous troops march on Sofia to declare a republic.
September 28 - Start of Allied offensive in Flanders.
September 29 - British, Australian, and American troops open main offensive on Hindenburg Line; Bulgaria signs armistice after talks at Salonika.
October 1 - Allenby and Lawrence arrive simultaneously at Damascus.
October 24 - Allies attack on wide front and win battle of Vittorio Veneto, followed by rout of Austrian army with mass desertions of Czech, Serb, Croat, and Polish troops.
October 26 - General Ludendorff resigns.
October 30 - Ottoman Empire sues for peace.
November 3 - Austria-Hungary signs armistice.
November 9 - Kaiser Wilhelm II abdicates.
November 11 - Armistice between Allies and Germany ends hostilities on the Western Front.