October 1915
| Date | Events |
|---|---|
| 2 | Greek Premier Venizelos asks British and French to land troops at Salonika as soon as possible |
| 3 | Allied troops begin arriving off Salonika: Greek government protests |
| 3 | "Livonia" becomes first German merchant ship sunk (in Baltic) by British submarine |
| 4 | Entente Powers send ultimatum to Bulgaria: Russia also severs diplomatic relations with Bulgaria (5 Oct) |
| 5 | Allied troops begin landing at Salonika. King Constantine refuses to support the policy of his Premier; Venizelos resigns |
| 6 | Austrian-German invasion of Serbia begins |
| 6 | King Constantine of Greece assures Britain that his country will remain neutral, but nonetheless Greek mobilisation proceeds |
| 8 | New Greek government, with Zaimis as new Premier, confims position of neutrality |
| 9 | Austrian forces capture Belgrade |
| 9 | Fighting again at Hafiz Kor on North West frontier of India |
| 10 | Greek government rejects Serbian plea for help against invasion |
| 11 | Bulgarian forces commence hostilities against Serbia |
| 12 | British nurse Edith Cavell executed by Germans after court-martial |
| 13 | Airship raid on East coast of England causes 200 casualties |
| 13 | Last large scale attack in Battle of Loos(against the Hohenzollern Redoubt) |
| 13 | French forces commence hostilities against Bulgarians in Macedonia |
| 14 | Bulgaria and Serbia declare war on each other |
| 15 | Britain declares state of war with Bulgaria, as does Montenegro |
| 15 | Rumanian government refuses assistance for Serbia |
| 15 | Bulgarian forces capture Vranje in Serbia |
| 15 | Gen. Sir Charles Munro appointed to succeed Ian Hamilton as Commnedr-in-Chief of Mediterranean Expeditionary Force: takes command 28 Oct |
| 16 | France declares state of war with Bulgaria |
| 16 | British government offers Cyprus to Greece is she will support Serbia: Greeks reject this (20 Oct) |
| 16 | Allies begin naval blockade of Aegean coast of Bulgaria |
| 18 | Third Battle of the Isonzo begins |
| 19 | Bulgarian forces capture Ishtip in Serbia |
| 19 | Russia and italy declare war on Bulgaria |
| 21 | Allied naval squadron bombards Dedeagatch in Bulgaria |
| 21 | Bulgarian forces capture Veles in Serbia |
| 22 | Bulgarian forces capture Kumanovo and Skopje (Uskub) in Macedonia |
| 24 | British letter to Sherif of Mecca defines boundaries of proposed Arab state |
| 29 | Viviani resigns as French Premier, as does Minister for War Millerand |
| 30 | Briand now French Premier and Gallieni is Minister for War |
| 30 | In Cameroons, Allies begin third attack on Mora |
| 30 | Last meeting of Dardanelles Committee of British Cabinet as decisions are taken to wind down Gallipoli campaign |