An unofficial Christmas truce takes place along some sections of the Western Front.
The Germans detonate ten mines under the British lines at Givenchy. This is the first large-scale use of underground mines on the Western Front.
The German navy shells the English coastal towns of Scarborough, Whitby and Hartlepool.
The Royal Navy is victorious against the Germans at the Battle of the Falklands in the South Atlantic.
British-Indian troops capture Qurna in Mesopotamia (now Iraq).
British-Indian forces defeat a tribal uprising in Waziristan on the North-West Frontier of India (now part of Pakistan).
The Battle of Basra in Mesopotamia (now Iraq) ends in a British-Indian victory against the Ottomans.
The ruler of the Ottoman Empire, Sultan Mehmed V, declares holy war on the Allies.
British-Indian troops drive back an Ottoman force threatening the British base at Aden.
The Australian navy secures victory over the Germans at the Battle of Cocos, in the eastern Indian Ocean.
British-Indian troops land at Fao in Mesopotamia (now Iraq), a territory of the Ottoman Empire.
The Germans secure victory over the British at the Battle of Kilimanjaro in German East Africa (now Tanzania).
The Russians launch an offensive against the Ottomans on the Caucasus front.
The Royal Navy begins blockading the coast of Germany.
The Germans win a naval victory against the British at the Battle of Coronel off the coast of Chile.
The First Battle of Ypres ends the ‘Race to the Sea’. The Germans are prevented from reaching the Channel ports, but the original British Expeditionary Force (BEF) is almost destroyed.
French and Belgian forces secure the Belgian coast with British naval support.
Part of the ‘Race to the Sea’: The Battle of Armentières, fought between British and German forces, is inconclusive.
Part of the ‘Race to the Sea’: The First Battle of Messines, fought between British and German forces, is inconclusive.
Part of the ‘Race to the Sea’: The Battle of La Bassée, fought between British and German forces, is inconclusive.
The Germans besiege and capture the city of Antwerp in Belgium.
The Germans are victorious against South African forces at the Battle of Sandfontein.
A Boer rebellion, led by General Manie Maritz against South Africa’s support for Britain and its invasion of German South-West Africa, is eventually suppressed.
General Erich von Falkenhayn replaces General Helmuth von Moltke the Younger as German Chief of Staff.
Allied attacks on the Germans during the First Battle of the Aisne end in stalemate. Both sides dig in. This leads to attempts at outflanking each other northwards in a so-called ‘Race to the Sea’.
Pro-British South African forces, under the command of General Louis Botha and General Jan Smuts, invade German South-West Africa (now Namibia).
Australia, a British ally, occupies German New Guinea (now part of Papua New Guinea).
The Austro-Hungarians fail in a second attempt at invading Serbia.
The Russians withdraw from East Prussia following defeat by Germany at the First Battle of the Masurian Lakes.
In the aftermath of the First Battle of the Marne, thick belts of barbed wire appear on the Western Front as both sides dig in.
The German advance on Paris is stopped at the First Battle of the Marne. This Allied victory marks the failure of the Schlieffen Plan and condemns Germany to a war on two fronts.
The Royal Naval Air Service deploys its vehicles on the Western Front, marking the first British combat use of armoured cars.
Part of the Battle of the Frontiers: The British are victorious at the Battle of Nery during the Retreat from Mons.
New Zealand, a British ally, occupies German Samoa (now Samoa).
Part of the Battle of the Frontiers: French success at the Battle of Saint Quentin (or the Battle of Guise) slows the German advance.
The Royal Navy is victorious against the Germans at the Battle of Heligoland Bight in the North Sea.
British and Japanese forces capture the German port of Tsingtao in China.
The Russians suffer a heavy defeat at German hands at Tannenberg in East Prussia.
Part of the Battle of the Frontiers: The British and French fight a successful holding action at Le Cateau during the Retreat from Mons.
British and French forces conquer Togoland (now Togo), a German protectorate in West Africa.
Part of the Battle of the Frontiers: The first major engagement of the British Expeditionary Force (BEF) leads to a retreat from Mons in Belgium.
The Germans capture Brussels, the capital city of Belgium.
A German attack at the Battle of Gumbinnen fails to stop the Russian advance in East Prussia. It also leads to reinforcements being transferred east from the Western Front, thus weakening the Schlieffen Plan’s chances of success.
The Russians invade East Prussia, but are temporarily checked by the Germans at the Battle of Stalluponen.
The Serbs defeat the invading Austro-Hungarians in the first major Allied victory of the First World War. This battle also sees the first aerial dogfight when the pilots of Serbian and Austro-Hungarian reconnaissance aircraft engage each other with small arms.
Four squadrons from the Royal Flying Corps join the British Expeditionary Force in France.
The Germans’ Schlieffen Plan meets with initial success in a series of engagements fought against the Allies in southern Belgium and eastern France.
Field Marshal Sir John French’s British Expeditionary Force (BEF) arrives in France.
The British Secretary of State for War, Lord Kitchener, calls for 100,000 volunteers for his ‘New Armies’.
The Germans besiege and then capture the fortresses of Liège in Belgium.
The Ottomans close the Dardanelles Strait, a shipping route linking the Black Sea and the Mediterranean.
Britain declares war on Germany following the latter’s violation of the Treaty of London (1839), which guaranteed Belgian neutrality.
As part of its plan to attack France, Germany invades Belgium aiming to outflank and encircle much of the French Army.
Foreign Secretary, Sir Edward Grey, addresses Parliament on the war in Europe and outlines the pros and cons of a British intervention.
Germany declares war on France (an ally of Russia) and neutral Belgium. The Germans’ Schlieffen Plan is based on a quick strike against France while Russia is slowly mobilising.
Germany and the Ottoman Empire (now Turkey) sign a secret alliance treaty aimed against Russia.
Germany warns Russia to cease mobilisation despite the latter’s claim that this is only aimed against the Austro-Hungarians.
Austria-Hungary declares war on Serbia. Russia mobilises in support of its Serb ally.
Austria-Hungary sends Serbia an impossible ultimatum, which is rejected.
Germany assures Austria-Hungary of its support against Russia should the latter oppose Austria’s planned attack on Serbia.
The heir to the Austro-Hungarian throne, Archduke Franz Ferdinand, is assassinated by a Bosnian Serb in Sarajevo. The Austro-Hungarians blame the Serbs and seek revenge.