World War I Clockwise from top: trenches on the Western Front; a British Mark IV Tank crossing a trench; Royal Navy battleship HMS Irresistible sinking after striking a mine at the Battle of the Dardanelles; a Vickers machine gun crew with gas masks, and German Albatros D.III biplanes Date 28 July 1914 – 11 November 1918 (Armistice) Treaty of Versailles signed 28 June 1919 Treaty of Saint-Germain-en-Laye signed 10 September 1919 Treaty of Neuilly-sur-Seine signed 27 November 1919 Treaty of Trianon signed 4 June 1920 Treaty of Sèvres signed 10 August 1920 Location Europe, Africa, the Middle East, the Pacific Islands, China and off the coast of South and North America Result Allied victory End of the German, Russian, Ottoman, and Austro-Hungarian empires Formation of new countries in Europe and the Middle East Transfer of German colonies and regions of the former Ottoman Empire to other powers Establishment of the League of Nations. (more...) Belligerents Allied (Entente) Powers French Third Republic British Empire  Russia (1914–17)  Italy (1915–18)  United States (1917–18)  Romania (1916–18) Empire of Japan Kingdom of Serbia  Belgium  Greece (1917–18) and others Central Powers German Empire  Austria-Hungary  Ottoman Empire  Bulgaria (1915–18) Commanders and leaders Leaders and commanders Raymond Poincaré Georges Clemenceau Ferdinand Foch H. H. Asquith David Lloyd George Douglas Haig Nicholas II Nicholas Nikolaevich Antonio Salandra Vittorio Orlando Luigi Cadorna Woodrow Wilson John J. Pershing Ferdinand I and others Leaders and commanders Wilhelm II Paul von Hindenburg Erich Ludendorff Franz Joseph I Karl I Conrad von Hötzendorf Mehmed V Enver Pasha Mustafa Kemal Ferdinand I Nikola Zhekov and others Strength Entente[1] 12,000,000 8,841,541[2][3] 8,660,000[4] 5,093,140 4,743,826 1,234,000 800,000 707,343 380,000 250,000 Total: 42,959,850 Central Powers[1] 13,250,000 7,800,000 2,998,321 1,200,000 Total: 25,248,321 Casualties and losses Military dead: 5,525,000 Military wounded: 12,831,500 Military missing: 4,121,000 Total: 22,477,500 KIA, WIA or MIA ...further details. Military dead: 4,386,000 Military wounded: 8,388,000 Military missing: 3,629,000 Total: 16,403,000 KIA, WIA or MIA ...further details.

v t e Theatres of World War I European: Balkans Western Front Eastern Front Italian Front Middle Eastern: Caucasus Persia Gallipoli Mesopotamia Sinai and Palestine South Arabia African: South-West Africa West Africa East Africa North Africa Asian and Pacific theatre Other theatres: America Atlantic Ocean Mediterranean

World War I (WWI), which was predominantly called the World War or the Great War from its occurrence until 1939 (World War II), and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers,^[5] which were assembled in two opposing alliances: the Allies (based on the Triple Entente of the United Kingdom, France and Russia) and the Central Powers (originally centred around the Triple Alliance of Germany, Austria-Hungary and Italy; but, as Austria–Hungary had taken the offensive against the agreement, Italy did not enter into the war).^[6] These alliances both reorganised (Italy fought for the Allies), and expanded as more nations entered the war. Ultimately more than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history.^[7][8] More than 9 million combatants were killed, largely because of enormous increases in lethality of weapons, thanks to new technology, without corresponding improvements in protection or mobility. It was the sixth-deadliest conflict in world history, subsequently paving the way for various political changes such as revolutions in the nations involved.^[9]

Long-term causes of the war included the imperialistic foreign policies of the great powers of Europe, including the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, the Russian Empire, the British Empire, the French Republic, and Italy. The assassination on 28 June 1914 of Archduke Franz Ferdinand of Austria, the heir to the throne of Austria-Hungary, by a Yugoslav nationalist in Sarajevo, Bosnia and Herzegovina was the proximate trigger of the war. It resulted in a Habsburg ultimatum against the Kingdom of Serbia.^[10][11] Several alliances formed over the previous decades were invoked, so within weeks the major powers were at war; via their colonies, the conflict soon spread around the world.

On 28 July, the conflict opened with the Austro-Hungarian invasion of Serbia,^[12][13] followed by the German invasion of Belgium, Luxembourg and France; and a Russian attack against Germany. After the German march on Paris was brought to a halt, the Western Front settled into a static battle of attrition with a trench line that changed little until 1917. In the East, the Russian army successfully fought against the Austro-Hungarian forces but was forced back from East Prussia and Poland by the German army. Additional fronts opened after the Ottoman Empire joined the war in 1914, Italy and Bulgaria in 1915 and Romania in 1916. The Russian Empire collapsed in March 1917, and Russia left the war after the October Revolution later that year. After a 1918 German offensive along the western front, United States forces entered the trenches and the Allies drove back the German armies in a series of successful offensives. Germany, which had its own trouble with revolutionaries at this point, agreed to a cease-fire on 11 November 1918, later known as Armistice Day. The war had ended in victory for the Allies.

Events on the home fronts were as tumultuous as on the battle fronts, as the participants tried to mobilize their manpower and economic resources to fight a total war. By the end of the war, four major imperial powers — the German, Russian, Austro-Hungarian and Ottoman empires — ceased to exist. The successor states of the former two lost a great amount of territory, while the latter two were dismantled entirely. The map of central Europe was redrawn into several smaller states.^[14] The League of Nations was formed in the hope of preventing another such conflict. The European nationalism spawned by the war and the breakup of empires, the repercussions of Germany's defeat and problems with the Treaty of Versailles are agreed to be factors contributing to World War II.^[15]

Names[link]

In Canada, Maclean's Magazine in October 1914 said, "Some wars name themselves. This is the Great War."^[16] During the Interwar period, the war was most often called the World War and the Great War, in English-speaking countries.

After the onset of the Second World War in 1939, the terms World War I or the First World War became standard, with British and Canadian historians favouring the First World War, and Americans World War I. The notion that the "World War" was merely the first in a series was not a new idea at the time, however; it was first introduced in September 1914 by German philosopher Ernst Haeckel, who claimed that "there is no doubt that the course and character of the feared 'European War' ... will become the first world war in the full sense of the word."^[17] The First World War was the title of a 1920 history by the officer and journalist Charles à Court Repington.

Background[link]

Map of the participants in World War I: Allied Powers in green, Central Powers in orange, and neutral countries in grey

In the 19th century, the major European powers had gone to great lengths to maintain a balance of power throughout Europe, resulting by 1900 in a complex network of political and military alliances throughout the continent.^[6] These had started in 1815, with the Holy Alliance between Prussia, Russia, and Austria. Then, in October 1873, German Chancellor Bismarck negotiated the League of the Three Emperors (German: Dreikaiserbund) between the monarchs of Austria–Hungary, Russia and Germany. This agreement failed because Austria–Hungary and Russia could not agree over Balkan policy, leaving Germany and Austria–Hungary in an alliance formed in 1879, called the Dual Alliance. This was seen as a method of countering Russian influence in the Balkans as the Ottoman Empire continued to weaken.^[6] In 1882, this alliance was expanded to include Italy in what became the Triple Alliance.^[18]

After 1870, European conflict was averted largely through a carefully planned network of treaties between the German Empire and the remainder of Europe orchestrated by Bismarck. He especially worked to hold Russia at Germany's side to avoid a two-front war with France and Russia. When Wilhelm II ascended to the throne as German Emperor (Kaiser), Bismarck's alliances were gradually de-emphasised. For example, the Kaiser refused to renew the Reinsurance Treaty with Russia in 1890. Two years later, the Franco-Russian Alliance was signed to counteract the force of the Triple Alliance. In 1904, the United Kingdom sealed an alliance with France, the Entente Cordiale, and in 1907, the United Kingdom and Russia signed the Anglo-Russian Convention. This system of interlocking bilateral agreements formed the Triple Entente.^[6]

HMS Dreadnought. A naval arms race existed between the United Kingdom and Germany.

German industrial and economic power had grown greatly after unification and the foundation of the Empire in 1871. From the mid-1890s on, the government of Wilhelm II used this base to devote significant economic resources to building up the Kaiserliche Marine (Imperial German Navy), established by Admiral Alfred von Tirpitz, in rivalry with the British Royal Navy for world naval supremacy.^[19] As a result, each nation strove to out-build the other in terms of capital ships. With the launch of HMS Dreadnought in 1906, the British Empire expanded on its significant advantage over its German rival.^[19] The arms race between Britain and Germany eventually extended to the rest of Europe, with all the major powers devoting their industrial base to producing the equipment and weapons necessary for a pan-European conflict.^[20] Between 1908 and 1913, the military spending of the European powers increased by 50 percent.^[21]

Gavrilo Princip, a Bosnian-Serb student, was arrested immediately after he assassinated Archduke Franz Ferdinand of Austria

Austria-Hungary precipitated the Bosnian crisis of 1908–1909 by officially annexing the former Ottoman territory of Bosnia and Herzegovina, which it had occupied since 1878. This angered the Kingdom of Serbia and its patron, the Pan-Slavic and Orthodox Russian Empire.^[22] Russian political manoeuvring in the region destabilised peace accords that were already fracturing in what was known as "the powder keg of Europe".^[22]

Ethno-linguistic map of Austria–Hungary, 1910

In 1912 and 1913 the First Balkan War was fought between the Balkan League and the fracturing Ottoman Empire. The resulting Treaty of London further shrank the Ottoman Empire, creating an independent Albanian State while enlarging the territorial holdings of Bulgaria, Serbia, Montenegro, and Greece. When Bulgaria attacked both Serbia and Greece on 16 June 1913, it lost most of Macedonia to Serbia and Greece and Southern Dobruja to Romania in the 33-day Second Balkan War, further destabilising the region.^[23]

On 28 June 1914, Gavrilo Princip, a Bosnian-Serb student and member of Young Bosnia, assassinated the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand of Austria in Sarajevo, Bosnia.^[24] This began a period of diplomatic manoeuvring among Austria-Hungary, Germany, Russia, France, and Britain called the July Crisis. Wanting to finally end Serbian interference in Bosnia, Austria-Hungary delivered the July Ultimatum to Serbia, a series of ten demands intentionally made unacceptable, intending to provoke a war with Serbia.^[25] When Serbia agreed to only eight of the ten demands, Austria-Hungary declared war on 28 July 1914. Strachan argues, "Whether an equivocal and early response by Serbia would have made any difference to Austria-Hungary's behaviour must be doubtful. Franz Ferdinand was not the sort of personality who commanded popularity, and his demise did not cast the empire into deepest mourning".^[26]

The Russian Empire, unwilling to allow Austria–Hungary to eliminate its influence in the Balkans, and in support of its longtime Serb protégés, ordered a partial mobilisation one day later.^[18] When the German Empire began to mobilise on 30 July 1914, France, resentful of the German conquest of Alsace-Lorraine during the Franco-Prussian War, ordered French mobilisation on 1 August. Germany declared war on Russia on the same day.^[27] The United Kingdom declared war on Germany on 4 August 1914, following an "unsatisfactory reply" to the British ultimatum that Belgium must be kept neutral.^[28]

Theatres of conflict[link]

Opening hostilities[link]

Confusion among the Central Powers[link]

The strategy of the Central Powers suffered from miscommunication. Germany had promised to support Austria-Hungary's invasion of Serbia, but interpretations of what this meant differed. Previously tested deployment plans had been replaced early in 1914, but the replacements had never been tested in exercises. Austro-Hungarian leaders believed Germany would cover its northern flank against Russia.^[29] Germany, however, envisioned Austria-Hungary directing most of its troops against Russia, while Germany dealt with France. This confusion forced the Austro-Hungarian Army to divide its forces between the Russian and Serbian fronts.

On 9 September 1914, the Septemberprogramm, a possible plan which detailed Germany's specific war aims and the conditions that Germany sought to force on the Allied Powers, was outlined by German Chancellor Theobald von Bethmann-Hollweg. It was never officially adopted.

African campaigns[link]

Lettow surrendering his forces to the British at Abercorn

Some of the first clashes of the war involved British, French, and German colonial forces in Africa. On 7 August, French and British troops invaded the German protectorate of Togoland. On 10 August, German forces in South-West Africa attacked South Africa; sporadic and fierce fighting continued for the rest of the war. The German colonial forces in German East Africa, led by Colonel Paul Emil von Lettow-Vorbeck, fought a guerrilla warfare campaign during World War I and only surrendered two weeks after the armistice took effect in Europe.^[30]

Serbian campaign[link]

Declaration of war. Austro-Hungarian government's telegram to the government of Serbia on 28 July 1914.

Austria invaded and fought the Serbian army at the Battle of Cer and Battle of Kolubara beginning on 12 August. Over the next two weeks Austrian attacks were thrown back with heavy losses, which marked the first major Allied victories of the war and dashed Austro-Hungarian hopes of a swift victory. As a result, Austria had to keep sizable forces on the Serbian front, weakening its efforts against Russia.^[31] Serbia’s defeat of the Austro-Hungarian invasion of 1914 counts among the major upset victories of the last century.^[32]

German forces in Belgium and France[link]

German soldiers in a railway goods van on the way to the front in 1914. A message on the car spells out "Trip to Paris"; early in the war all sides expected the conflict to be a short one.

At the outbreak of the First World War, the German army (consisting in the West of seven field armies) carried out a modified version of the Schlieffen Plan, designed to quickly attack France through neutral Belgium before turning southwards to encircle the French army on the German border.^[10] The plan called for the right flank of the German advance to converge on Paris, and initially the Germans were successful, particularly in the Battle of the Frontiers (14–24 August). By 12 September, the French, with assistance from the British forces, halted the German advance east of Paris at the First Battle of the Marne (5–12 September). The last days of this battle signified the end of mobile warfare in the west.^[10] The French offensive into Germany, launched on 7 August with the Battle of Mulhouse, had limited success.

In the east, only one field army defended East Prussia, and when Russia attacked in this region it diverted German forces intended for the Western Front. Germany defeated Russia in a series of battles collectively known as the First Battle of Tannenberg (17 August – 2 September), but this diversion aggravated problems of insufficient speed of advance from rail-heads not foreseen by the German General Staff. The Central Powers were denied a quick victory and forced to fight a war on two fronts. The German army had fought its way into a good defensive position inside France and had permanently incapacitated 230,000 more French and British troops than it had lost itself. Despite this, communications problems and questionable command decisions cost Germany the chance of early victory.^[33]

Asia and the Pacific[link]

New Zealand occupied German Samoa (later Western Samoa) on 30 August. On 11 September, the Australian Naval and Military Expeditionary Force landed on the island of Neu Pommern (later New Britain), which formed part of German New Guinea. Japan seized Germany's Micronesian colonies and, after the Siege of Tsingtao, the German coaling port of Qingdao in the Chinese Shandong peninsula. Within a few months, the Allied forces had seized all the German territories in the Pacific; only isolated commerce raiders and a few holdouts in New Guinea remained.^[34][35]

Early stages[link]

Trench warfare begins[link]

Sir Winston Churchill with the Royal Scots Fusiliers, 1916

Sunlight Soap ad, placed in a trench (1915)

Military tactics before World War I had failed to keep pace with advances in technology. These advances allowed for impressive defence systems, which out-of-date military tactics could not break through for most of the war. Barbed wire was a significant hindrance to massed infantry advances. Artillery, vastly more lethal than in the 1870s, coupled with machine guns, made crossing open ground extremely difficult.^[36] The Germans introduced poison gas; it soon became used by both sides, though it never proved decisive in winning a battle. Its effects were brutal, causing slow and painful death, and poison gas became one of the most-feared and best-remembered horrors of the war.^{[citation needed]} Commanders on both sides failed to develop tactics for breaching entrenched positions without heavy casualties.

In time, however, technology began to produce new offensive weapons, such as the tank.^[37] Britain and France were its primary users; the Germans employed captured Allied tanks and small numbers of their own design. After the First Battle of the Marne, both Entente and German forces began a series of outflanking manoeuvres, in the so-called "Race to the Sea". Britain and France soon found themselves facing entrenched German forces from Lorraine to Belgium's coast.^[10] Britain and France sought to take the offensive, while Germany defended the occupied territories; consequently, German trenches were much better constructed than those of their enemy. Anglo-French trenches were only intended to be "temporary" before their forces broke through German defences.^[38] Both sides tried to break the stalemate using scientific and technological advances. On 22 April 1915 at the Second Battle of Ypres, the Germans (violating the Hague Convention) used chlorine gas for the first time on the Western Front. Algerian troops retreated when gassed and a six-kilometre (four-mile) hole opened in the Allied lines that the Germans quickly exploited, taking Kitcheners' Wood. Canadian soldiers closed the breach at the Second Battle of Ypres.^[39] At the Third Battle of Ypres, Canadian and ANZAC troops took the village of Passchendaele.

Men in Melbourne collecting recruitment papers

In the trenches: Royal Irish Rifles in a communications trench on the first day on the Somme, 1 July 1916.

On 1 July 1916, the British Army endured the bloodiest day in its history, suffering 57,470 casualties, including 19,240 dead, on the first day of the Battle of the Somme. Most of the casualties occurred in the first hour of the attack. The entire Somme offensive cost the British Army almost half a million men.^[40]

Neither side proved able to deliver a decisive blow for the next two years, though protracted German action at Verdun throughout 1916,^[41] combined with the bloodletting at the Somme, brought the exhausted French army to the brink of collapse. Futile attempts at frontal assault came at a high price for both the British and the French poilu (infantry) and led to widespread mutinies, especially during the Nivelle Offensive.^[42]

Canadian troops advancing behind a British Mark II tank at the Battle of Vimy Ridge.

A French assault on German positions. Champagne, France, 1917.

Officers and senior enlisted men of the Bermuda Militia Artillery's Bermuda Contingent, Royal Garrison Artillery, in Europe.

A battleship squadron of the Hochseeflotte at sea

Throughout 1915–17, the British Empire and France suffered more casualties than Germany, because of both the strategic and tactical stances chosen by the sides. Strategically, while the Germans only mounted a single main offensive at Verdun, the Allies made several attempts to break through German lines. Tactically, German commander Erich Ludendorff's doctrine of "elastic defence" was well suited for trench warfare. This defence had a lightly defended forward position and a more powerful main position farther back beyond artillery range, from which an immediate and powerful counter-offensive could be launched.^[43][44]

Ludendorff wrote on the fighting in 1917,

The 25th of August concluded the second phase of the Flanders battle. It had cost us heavily ... The costly August battles in Flanders and at Verdun imposed a heavy strain on the Western troops. In spite of all the concrete protection they seemed more or less powerless under the enormous weight of the enemy's artillery. At some points they no longer displayed the firmness which I, in common with the local commanders, had hoped for. The enemy managed to adapt himself to our method of employing counter attacks ... I myself was being put to a terrible strain. The state of affairs in the West appeared to prevent the execution of our plans elsewhere. Our wastage had been so high as to cause grave misgivings, and had exceeded all expectation.^[45]

On the battle of the Menin Road Ridge, Ludendorff wrote,

Another terrific assault was made on our lines on the 20 September ... The enemy's onslaught on the 20th was successful, which proved the superiority of the attack over the defence. Its strength did not consist in the tanks; we found them inconvenient, but put them out of action all the same. The power of the attack lay in the artillery, and in the fact that ours did not do enough damage to the hostile infantry as they were assembling, and above all, at the actual time of the assault.^[46]

Around 1.1 to 1.2 million soldiers from the British and Dominion armies were on the Western Front at any one time.^[47] A thousand battalions, occupying sectors of the line from the North Sea to the Orne River, operated on a month-long four-stage rotation system, unless an offensive was underway. The front contained over 9,600 kilometres (5,965 mi) of trenches. Each battalion held its sector for about a week before moving back to support lines and then further back to the reserve lines before a week out-of-line, often in the Poperinge or Amiens areas.

In the 1917 Battle of Arras, the only significant British military success was the capture of Vimy Ridge by the Canadian Corps under Sir Arthur Currie and Julian Byng. The assaulting troops could, for the first time, overrun, rapidly reinforce and hold the ridge defending the coal-rich Douai plain.^[48][49]

Naval war[link]

At the start of the war, the German Empire had cruisers scattered across the globe, some of which were subsequently used to attack Allied merchant shipping. The British Royal Navy systematically hunted them down, though not without some embarrassment from its inability to protect Allied shipping. For example, the German detached light cruiser SMS Emden, part of the East-Asia squadron stationed at Tsingtao, seized or destroyed 15 merchantmen, as well as sinking a Russian cruiser and a French destroyer. However, most of the German East-Asia squadron—consisting of the armoured cruisers Scharnhorst and Gneisenau, light cruisers Nürnberg and Leipzig and two transport ships—did not have orders to raid shipping and was instead underway to Germany when it met British warships. The German flotilla and Dresden sank two armoured cruisers at the Battle of Coronel, but was almost destroyed at the Battle of the Falkland Islands in December 1914, with only Dresden and a few auxiliaries escaping, but at the Battle of Más a Tierra these too were destroyed or interned.^[50]

Soon after the outbreak of hostilities, Britain began a naval blockade of Germany. The strategy proved effective, cutting off vital military and civilian supplies, although this blockade violated accepted international law codified by several international agreements of the past two centuries.^[51] Britain mined international waters to prevent any ships from entering entire sections of ocean, causing danger to even neutral ships.^[52] Since there was limited response to this tactic, Germany expected a similar response to its unrestricted submarine warfare.^[53]

The 1916 Battle of Jutland (German: Skagerrakschlacht, or "Battle of the Skagerrak") developed into the largest naval battle of the war, the only full-scale clash of battleships during the war, and one of the largest in history. It took place on 31 May – 1 June 1916, in the North Sea off Jutland. The Kaiserliche Marine's High Seas Fleet, commanded by Vice Admiral Reinhard Scheer, squared off against the Royal Navy's Grand Fleet, led by Admiral Sir John Jellicoe. The engagement was a stand off, as the Germans, outmanoeuvred by the larger British fleet, managed to escape and inflicted more damage to the British fleet than they received. Strategically, however, the British asserted their control of the sea, and the bulk of the German surface fleet remained confined to port for the duration of the war.^[54]

German U-boats attempted to cut the supply lines between North America and Britain.^[55] The nature of submarine warfare meant that attacks often came without warning, giving the crews of the merchant ships little hope of survival.^[55][56] The United States launched a protest, and Germany changed its rules of engagement. After the notorious sinking of the passenger ship RMS Lusitania in 1915, Germany promised not to target passenger liners, while Britain armed its merchant ships, placing them beyond the protection of the "cruiser rules" which demanded warning and placing crews in "a place of safety" (a standard which lifeboats did not meet).^[57] Finally, in early 1917 Germany adopted a policy of unrestricted submarine warfare, realising the Americans would eventually enter the war.^[55][58] Germany sought to strangle Allied sea lanes before the U.S. could transport a large army overseas, but could maintain only five long-range U-boats on station, to limited effect.^[55]

U-155 exhibited near Tower Bridge in London after the First World War.

The U-boat threat lessened in 1917, when merchant ships began travelling in convoys, escorted by destroyers. This tactic made it difficult for U-boats to find targets, which significantly lessened losses; after the hydrophone and depth charges were introduced, accompanying destroyers might attack a submerged submarine with some hope of success. Convoys slowed the flow of supplies, since ships had to wait as convoys were assembled. The solution to the delays was an extensive program to build new freighters. Troopships were too fast for the submarines and did not travel the North Atlantic in convoys.^[59] The U-boats had sunk more than 5,000 Allied ships, at a cost of 199 submarines.^[60]

World War I also saw the first use of aircraft carriers in combat, with HMS Furious launching Sopwith Camels in a successful raid against the Zeppelin hangars at Tondern in July 1918, as well as blimps for antisubmarine patrol.^[61]

Southern theatres[link]

War in the Balkans[link]

Austrian troops executing captured Serbians. Serbia lost about 850,000 people, a quarter of its pre-war population.^[62]

Faced with Russia, Austria-Hungary could spare only one-third of its army to attack Serbia. After suffering heavy losses, the Austrians briefly occupied the Serbian capital, Belgrade. A Serbian counter attack in the battle of Kolubara, however, succeeded in driving them from the country by the end of 1914. For the first ten months of 1915, Austria-Hungary used most of its military reserves to fight Italy. German and Austro-Hungarian diplomats, however, scored a coup by persuading Bulgaria to join in attacking Serbia. The Austro-Hungarian provinces of Slovenia, Croatia and Bosnia provided troops for Austria-Hungary, invading Serbia as well as fighting Russia and Italy. Montenegro allied itself with Serbia.^[63]

Serbia was conquered in a little more than a month, as the Central Powers, now including Bulgaria, sent in 600,000 troops. The Serbian army, fighting on two fronts and facing certain defeat, retreated into northern Albania (which they had invaded at the beginning of the war). The Serbs suffered defeat in the Battle of Kosovo. Montenegro covered the Serbian retreat towards the Adriatic coast in the Battle of Mojkovac in 6–7 January 1916, but ultimately the Austrians conquered Montenegro, too. The surviving 70,000 Serbian soldiers were evacuated by ship to Greece.^[64]

In late 1915, a Franco-British force landed at Salonica in Greece, to offer assistance and to pressure the government to declare war against the Central Powers. Unfortunately for the Allies, the pro-German King Constantine I dismissed the pro-Allied government of Eleftherios Venizelos, before the Allied expeditionary force could arrive.^[65] The friction between the king of Greece and the Allies continued to accumulate with the National Schism, which effectively divided Greece between regions still loyal to the king and the new provisional government of Venizelos in Salonica. After intensive diplomatic negotiations and an armed confrontation in Athens between Allied and royalist forces (an incident known as Noemvriana) the king of Greece resigned, and his second son Alexander took his place. Venizelos returned to Athens on 29 May 1917 and Greece, now unified, officially joined the war on the side of the Allies. The entire Greek army was mobilized and began to participate in military operations against the Central Powers on the Macedonian front.

Bulgarian soldiers in a trench, preparing to fire against an incoming airplane

After conquest, Serbia was divided between Austro-Hungary and Bulgaria. In 1917 the Serbs launched the Toplica Uprising and liberated for a short time the area between the Kopaonik mountains and the South Morava river. The uprising was crushed by joint efforts of Bulgarian and Austrian forces at the end of March 1917.

The Macedonian Front in the beginning was mostly static. French and Serbian forces retook limited areas of Macedonia by recapturing Bitola on 19 November 1916 as a result of the costly Monastir Offensive which brought stabilization of the front.

Serbian and French troops finally made a breakthrough, after most of the German and Austro-Hungarian troops had withdrawn. This breakthrough was significant in defeating Bulgaria and Austro-Hungary, which led to the final victory of WWI. The Bulgarians suffered their only defeat of the war at the Battle of Dobro Pole but days later, they decisively defeated British and Greek forces at the Battle of Doiran, avoiding occupation. After Serbian breakthrough of Bulgarian lines, Bulgaria capitulated on 29 September 1918.^[66] Hindenburg and Ludendorff concluded that the strategic and operational balance had now shifted decidedly against the Central Powers and a day after the Bulgarian collapse, during a meeting with government officials, insisted on an immediate peace settlement.^[67]

The disappearance of the Macedonian front meant that the road to Budapest and Vienna was now opened for the 670,000-strong army of general Franchet d'Esperey as the Bulgarian surrender deprived the Central Powers of the 278 infantry battalions and 1,500 guns (the equivalent of some 25 to 30 German divisions) that were previously holding the line.^[68] The German high command responded by sending only seven infantry and one cavalry division but these forces were far from enough for a front to be reestablished.^[68]

Ottoman Empire[link]

The Ottoman Empire joined the Central Powers in the war, the secret Ottoman-German Alliance having been signed in August 1914.^[69] It threatened Russia's Caucasian territories and Britain's communications with India via the Suez Canal. The British and French opened overseas fronts with the Gallipoli (1915) and Mesopotamian campaigns. In Gallipoli, the Ottoman Empire successfully repelled the British, French, and Australian and New Zealand Army Corps (ANZACs). In Mesopotamia, by contrast, after the disastrous Siege of Kut (1915–16), British Imperial forces reorganised and captured Baghdad in March 1917.

A British artillery battery emplaced on Mount Scopus in the Battle of Jerusalem.

Further to the west, the Suez Canal was successfully defended from Ottoman attacks in 1915 and 1916; in August a joint German and Ottoman force was defeated at the Battle of Romani by the Anzac Mounted and the 52nd (Lowland) Infantry Divisions. Following this victory, a British Empire Egyptian Expeditionary Force advanced across the Sinai Peninsula, pushing Ottoman forces back in the Battle of Magdhaba in December and the Battle of Rafa on the border between the Egyptian Sinai and Ottoman Palestine in January 1917. In March and April at the First and Second Battles of Gaza, German and Ottoman forces stopped the advance, but at the end of October the Sinai and Palestine Campaign resumed, when Allenby's XXth Corps, XXI Corps and Desert Mounted Corps won the Battle of Beersheba. Two Ottoman armies were defeated a few weeks later at the Battle of Mughar Ridge, and early in December Jerusalem was captured following another Ottoman defeat at the Battle of Jerusalem (1917). About this time Friedrich Freiherr Kress von Kressenstein was relieved of his duties as the Eighth Army's commander, replaced by Djevad Pasha, and a few months later the commander of the Ottoman Army in Palestine, Erich von Falkenhayn, was replaced by Otto Liman von Sanders.

A reorganised Egyptian Expeditionary Force, with an additional mounted division under Field Marshal Edmund Allenby, broke Ottoman forces at the Battle of Megiddo in September 1918. In six weeks, during virtually continuous operations, battles were successfully fought by British infantry and Australian, British, Indian and New Zealand, Light Horse, mounted Yeomanry, Lancers and Mounted Rifle brigades. They campaigned across the Jordan River to Amman in the east and northwards to capture Nablus and Tulkarm in the Judean Hills, and followed the Mediterranean coast into the Jezreel Valley (Esdraelon Plain), where Afula, Jenin and Nazareth were captured, along with Daraa east of the Jordan River on the Hejaz railway. Semakh and Tiberias on the Sea of Gallilee, were captured on the way northwards to Damascus and Aleppo. The Armistice of Mudros was signed on 30 October, when two and a half Ottoman armies had been defeated and captured.

Russian forest trench at the Battle of Sarikamish

Russian armies generally had the best of it in the Caucasus. Enver Pasha, supreme commander of the Ottoman armed forces, was ambitious and dreamed of re-conquering central Asia and areas that had been lost to Russia previously. He was, however, a poor commander.^[70] He launched an offensive against the Russians in the Caucasus in December 1914 with 100,000 troops; insisting on a frontal attack against mountainous Russian positions in winter, he lost 86% of his force at the Battle of Sarikamish.^[71]

General Yudenich, the Russian commander from 1915 to 1916, drove the Turks out of most of the southern Caucasus with a string of victories.^[71] In 1917, Russian Grand Duke Nicholas assumed command of the Caucasus front. Nicholas planned a railway from Russian Georgia to the conquered territories, so that fresh supplies could be brought up for a new offensive in 1917. However, in March 1917 (February in the pre-revolutionary Russian calendar), the Czar was overthrown in the February Revolution and the Russian Caucasus Army began to fall apart.

German soldiers in Jerusalem

Instigated by the Arab bureau of the British Foreign Office, the Arab Revolt started with the help of Britain in June 1916 at the Battle of Mecca, led by Sherif Hussein of Mecca, and ended with the Ottoman surrender of Damascus. Fakhri Pasha, the Ottoman commander of Medina, resisted for more than two and half years during the Siege of Medina.^[72]

Along the border of Italian Libya and British Egypt, the Senussi tribe, incited and armed by the Turks, waged a small-scale guerrilla war against Allied troops. The British were forced to dispatch 12,000 troops to oppose them in the Senussi Campaign. Their rebellion was finally crushed in mid-1916.^[73]

Italian participation[link]

Austro-Hungarian mountain corps in Tyrol

Italy had been allied with the German and Austro-Hungarian Empires since 1882 as part of the Triple Alliance. However, the nation had its own designs on Austrian territory in Trentino, Istria, and Dalmatia. Rome had a secret 1902 pact with France, effectively nullifying its alliance.^[74] At the start of hostilities, Italy refused to commit troops, arguing that the Triple Alliance was defensive and that Austria–Hungary was an aggressor. The Austro-Hungarian government began negotiations to secure Italian neutrality, offering the French colony of Tunisia in return. The Allies made a counter-offer in which Italy would receive the Southern Tyrol, Julian March and territory on the Dalmatian coast after the defeat of Austria-Hungary. This was formalised by the Treaty of London. Further encouraged by the Allied invasion of Turkey in April 1915, Italy joined the Triple Entente and declared war on Austria-Hungary on 23 May. Fifteen months later Italy declared war on Germany.

a Hungarian soldier on the Italian front

Militarily, the Italians had numerical superiority. This advantage, however, was lost, not only because of the difficult terrain in which fighting took place, but also because of the strategies and tactics employed. Field Marshal Luigi Cadorna, a staunch proponent of the frontal assault, had dreams of breaking into the Slovenian plateau, taking Ljubljana and threatening Vienna. Cadorna's plan did not take into account the difficulties of the rugged Alpine terrain, or the technological changes that created trench warfare, giving rise to a series of bloody and inconclusive stalemated offensives.

Depiction of the Battle of Doberdò, fought in August 1916 between the Italian and Austro-Hungarian army.

On the Trentino front, the Austro-Hungarians took advantage of the mountainous terrain, which favoured the defender. After an initial strategic retreat, the front remained largely unchanged, while Austrian Kaiserschützen and Standschützen engaged Italian Alpini in bitter hand-to-hand combat throughout the summer. The Austro-Hungarians counterattacked in the Altopiano of Asiago, towards Verona and Padua, in the spring of 1916 (Strafexpedition), but made little progress.

Beginning in 1915, the Italians under Cadorna mounted eleven offensives on the Isonzo front along the Isonzo River, northeast of Trieste. All eleven offensives were repelled by the Austro-Hungarians, who held the higher ground. In the summer of 1916, the Italians captured the town of Gorizia. After this minor victory, the front remained static for over a year, despite several Italian offensives. In the autumn of 1917, thanks to the improving situation on the Eastern front, the Austro-Hungarian troops received large numbers of reinforcements, including German Stormtroopers and the elite Alpenkorps. The Central Powers launched a crushing offensive on 26 October 1917, spearheaded by the Germans. They achieved a victory at Caporetto. The Italian Army was routed and retreated more than 100 kilometres (62 mi) to reorganise, stabilising the front at the Piave River. Since in the Battle of Caporetto the Italian Army had heavy losses, the Italian Government called to arms the so-called '99 Boys (Ragazzi del '99): that is, all males who were 18 years old. In 1918, the Austro-Hungarians failed to break through, in a series of battles on the Piave River, and were finally decisively defeated in the Battle of Vittorio Veneto in October of that year. From 5–6 November 1918, Italian forces were reported to have reached Lissa, Lagosta, Sebenico, and other localities on the Dalmatian coast.^[75] By the end of hostilities in November 1918, the Italian military had seized control of the entire portion of Dalmatia that had been guaranteed to Italy by the London Pact.^[76] In 1918, Admiral Enrico Millo declared himself Italy's Governor of Dalmatia.^[76] Austria-Hungary surrendered in early November 1918.^[77][78]

Romanian participation[link]

Marshal Joffre inspecting Romanian troops

Romania had been allied with the Central Powers since 1882. When the war began, however, it declared its neutrality, arguing that because Austria-Hungary had itself declared war on Serbia, Romania was under no obligation to join the war. When the Entente Powers promised Romania large territories of eastern Hungary (Transylvania and Banat) that had a large Romanian population in exchange for Romania's declaring war on the Central Powers, the Romanian government renounced its neutrality, and on 27 August 1916 the Romanian Army launched an attack against Austria-Hungary, with limited Russian support. The Romanian offensive was initially successful, pushing back the Austro-Hungarian troops in Transylvania, but a counterattack by the forces of the Central Powers drove back the Russo-Romanian forces. As a result of the Battle of Bucharest the Central Powers occupied Bucharest on 6 December 1916. Fighting in Moldova continued in 1917, resulting in a costly stalemate for the Central Powers.^[79][80] Russian withdrawal from the war in late 1917 as a result of the October Revolution meant that Romania was forced to sign an armistice with the Central Powers on 9 December 1917.

In January 1918, Romanian forces established control over Bessarabia as the Russian Army abandoned the province. Although a treaty was signed by the Romanian and the Bolshevik Russian government following talks from 5–9 March 1918 on the withdrawal of Romanian forces from Bessarabia within two months, on 27 March 1918 Romania attached Bessarabia to its territory, formally based on a resolution passed by the local assembly of the territory on the unification with Romania.

Romania officially made peace with the Central Powers by signing the Treaty of Bucharest on 7 May 1918. Under that treaty, Romania was obliged to end war with the Central Powers and make small territorial concessions to Austria-Hungary, ceding control of some passes in the Carpathian Mountains, and grant oil concessions to Germany. In exchange, the Central Powers recognised the sovereignty of Romania over Bessarabia. The treaty was renounced in October 1918 by the Alexandru Marghiloman government, and Romania nominally re-entered the war on 10 November 1918. The next day, the Treaty of Bucharest was nullified by the terms of the Armistice of Compiègne.^[81][82] Total Romanian deaths from 1914 to 1918, military and civilian, within contemporary borders, were estimated at 748,000.^[83]

The role of India[link]

Contrary to British fears of a revolt in India, the outbreak of the war saw an unprecedented outpouring of loyalty and good will towards the United Kingdom.^[84][85] Indian political leaders from the Indian National Congress and other groups were eager to support the British war effort since they believed that strong support for the war effort would further the cause of Indian Home Rule. The Indian Army in fact outnumbered the British Army at the beginning of the war; about 1.3 million Indian soldiers and labourers served in Europe, Africa, and the Middle East, while both the central government and the princely states sent large supplies of food, money, and ammunition. In all, 140,000 men served on the Western Front and nearly 700,000 in the Middle East. Casualties of Indian soldiers totalled 47,746 killed and 65,126 wounded during World War I.^[86] The suffering engendered by the war as well as the failure of the British government to grant self-government to India after the end of hostilities bred disillusionment and fuelled the campaign for full independence that would be led by Mohandas Karamchand Gandhi and others.

Russian troops awaiting a German attack

Eastern Front[link]

Initial actions[link]

While the Western Front had reached stalemate, the war continued in East Europe. Initial Russian plans called for simultaneous invasions of Austrian Galicia and German East Prussia. Although Russia's initial advance into Galicia was largely successful, it was driven back from East Prussia by Hindenburg and Ludendorff at Tannenberg and the Masurian Lakes in August and September 1914.^[87][88] Russia's less developed industrial base and ineffective military leadership was instrumental in the events that unfolded. By the spring of 1915, the Russians had retreated into Galicia, and in May the Central Powers achieved a remarkable breakthrough on Poland's southern frontiers.^[89] On 5 August they captured Warsaw and forced the Russians to withdraw from Poland.

Russian Revolution[link]

Vladimir Illyich Lenin

Despite the success of the June 1916 Brusilov Offensive in eastern Galicia,^[90] dissatisfaction with the Russian government's conduct of the war grew. The offensive's success was undermined by the reluctance of other generals to commit their forces to support the victory. Allied and Russian forces were revived only temporarily by Romania's entry into the war on 27 August. German forces came to the aid of embattled Austro-Hungarian units in Transylvania, and Bucharest fell to the Central Powers on 6 December. Meanwhile, unrest grew in Russia, as the Tsar remained at the front. Empress Alexandra's increasingly incompetent rule drew protests and resulted in the murder of her favourite, Rasputin, at the end of 1916.

In March 1917, demonstrations in Petrograd culminated in the abdication of Tsar Nicholas II and the appointment of a weak Provisional Government which shared power with the Petrograd Soviet socialists. This arrangement led to confusion and chaos both at the front and at home. The army became increasingly ineffective.^[89]

Russian Cossacks on the front, 1915

Signing the Treaty of Brest-Litovsk (9 February 1918) are: 1. Count Ottokar von Czernin, 2. Richard von Kühlmann, and 3. Vasil Radoslavov

Discontent and the weaknesses of the Provisional Government led to a rise in popularity of the Bolshevik Party, led by Vladimir Lenin, which demanded an immediate end to the war. The successful armed uprising by the Bolsheviks of November was followed in December by an armistice and negotiations with Germany. At first the Bolsheviks refused the German terms, but when German troops began marching across the Ukraine unopposed, the new government acceded to the Treaty of Brest-Litovsk on 3 March 1918. The treaty ceded vast territories, including Finland, the Baltic provinces, parts of Poland and Ukraine to the Central Powers.^[91] Despite this enormous apparent German success, the manpower required for German occupation of former Russian territory may have contributed to the failure of the Spring Offensive and secured relatively little food or other materiel.

With the adoption of the Treaty of Brest-Litovsk, the Entente no longer existed. The Allied powers led a small-scale invasion of Russia, partly to stop Germany from exploiting Russian resources and, to a lesser extent, to support the "Whites" (as opposed to the "Reds") in the Russian Civil War.^[92] Allied troops landed in Arkhangelsk and in Vladivostok.

Central Powers proposal for starting peace negotiations[link]

On the way to Verdun. "They shall not pass" is a phrase which for all time will be associated with the heroic defense of Verdun.

In December 1916, after ten brutal months of the Battle of Verdun and a successful offensive against Romania, the Germans attempted to negotiate a peace with the Allies. Soon after, U.S. President Woodrow Wilson attempted to intervene as a peacemaker, asking in a note for both sides to state their demands. Lloyd George's War Cabinet considered the German offer to be a ploy to create divisions amongst the Allies. After initial outrage and much deliberation, they took Wilson's note as a separate effort, signalling that the U.S. was on the verge of entering the war against Germany following the "submarine outrages". While the Allies debated a response to Wilson's offer, the Germans chose to rebuff it in favour of "a direct exchange of views". Learning of the German response, the Allied governments were free to make clear demands in their response of 14 January. They sought restoration of damages, the evacuation of occupied territories, reparations for France, Russia and Romania, and a recognition of the principle of nationalities. This included the liberation of Italians, Slavs, Romanians, Czecho-Slovaks, and the creation of a "free and united Poland". On the question of security, the Allies sought guarantees that would prevent or limit future wars, complete with sanctions, as a condition of any peace settlement.^[93] The negotiations failed and the Entente powers rejected the German offer, because Germany did not state any specific proposals. To Wilson, the Entente powers stated that they would not start peace negotiations until the Central powers evacuated all occupied Allied territories and provided indemnities for all damage which had been done.^[94]

1917–1918[link]

French troopers under General Gouraud, with their machine guns amongst the ruins of a cathedral near the Marne, driving back the Germans. 1918

German film crew recording the action.

Developments in 1917[link]

Events of 1917 proved decisive in ending the war, although their effects were not fully felt until 1918.

The British naval blockade began to have a serious impact on Germany. In response, in February 1917, the German General Staff convinced Chancellor Theobald von Bethmann-Hollweg to declare unrestricted submarine warfare, with the goal of starving Britain out of the war. German planners estimated that unrestricted submarine warfare would cost Britain a monthly shipping loss of 600,000 tons. The General Staff acknowledged that the policy would almost certainly bring the United States into the conflict, but calculated that British shipping losses would be so high that they would be forced to sue for peace after 5 to 6 months, before American intervention could make an impact. In reality, tonnage sunk rose above 500,000 tons per month from February to July. It peaked at 860,000 tons in April. After July, the newly re-introduced convoy system became extremely effective in reducing the U-boat threat. Britain was safe from starvation while German industrial output fell, and the United States troops joined the war in large numbers far earlier than Germany had anticipated.

On 3 May 1917, during the Nivelle Offensive, the weary French 2nd Colonial Division, veterans of the Battle of Verdun, refused their orders, arriving drunk and without their weapons. Their officers lacked the means to punish an entire division, and harsh measures were not immediately implemented. Then, mutinies afflicted an additional 54 French divisions and saw 20,000 men desert. The other Allied forces attacked but sustained tremendous casualties.^[95] However, appeals to patriotism and duty, as well as mass arrests and trials, encouraged the soldiers to return to defend their trenches, although the French soldiers refused to participate in further offensive action.^[96] Robert Nivelle was removed from command by 15 May, replaced by General Philippe Pétain, who suspended bloody large-scale attacks.

Haut-Rhin, France, 1917

The victory of Austria–Hungary and Germany at the Battle of Caporetto led the Allies at the Rapallo Conference to form the Supreme War Council to coordinate planning. Previously, British and French armies had operated under separate commands.

In December, the Central Powers signed an armistice with Russia. This released large numbers of German troops for use in the west. With German reinforcements and new American troops pouring in, the outcome was to be decided on the Western Front. The Central Powers knew that they could not win a protracted war, but they held high hopes for success based on a final quick offensive. Furthermore, the leaders of the Central Powers and the Allies became increasingly fearful of social unrest and revolution in Europe. Thus, both sides urgently sought a decisive victory.^[97]

Entry of the United States[link]

Non-intervention[link]

At the outbreak of the war the United States pursued a policy of non-intervention, avoiding conflict while trying to broker a peace. When a German U-boat sank the British liner RMS Lusitania on 7 May 1915 with 128 Americans among the dead, President Woodrow Wilson insisted that "America is too proud to fight" but demanded an end to attacks on passenger ships. Germany complied. Wilson unsuccessfully tried to mediate a settlement. However, he also repeatedly warned that the U.S.A. would not tolerate unrestricted submarine warfare, in violation of international law. Former president Theodore Roosevelt denounced German acts as "piracy".^[98] Wilson was narrowly reelected in 1916 as his supporters emphasized "he kept us out of war".

In January 1917, Germany resumed unrestricted submarine warfare, realizing it would mean American entry. The German Foreign Minister, in the Zimmermann Telegram, invited Mexico to join the war as Germany's ally against the United States. In return, the Germans would finance Mexico's war and help it recover the territories of Texas, New Mexico, and Arizona.^[99] Wilson released the Zimmerman note to the public, and Americans saw it as casus belli—a cause for war. Wilson called on antiwar elements to end all wars, by winning this one and eliminating militarism from the globe. He argued that the war was so important that the U.S. had to have a voice in the peace conference.^[100]

President Wilson before Congress, announcing the break in official relations with Germany on 3 February 1917.

U.S. declaration of war on Germany[link]

Wikisource has original text related to this article: Woodrow Wilson Urges Congress to Declare War on Germany

After the sinking of seven U.S. merchant ships by submarines and the publication of the Zimmerman telegram, Wilson called for war on Germany,^[101] which the U.S. Congress declared on 6 April 1917.

First active U.S. participation[link]

American soldiers on the Piave front hurling a shower of hand grenades into the Austrian trenches

Two Allied soldiers run towards a bunker.

The United States was never formally a member of the Allies but became a self-styled "Associated Power". The United States had a small army, but, after the passage of the Selective Service Act, it drafted 2.8 million men,^[102] and by summer 1918 was sending 10,000 fresh soldiers to France every day. In 1917, the U.S. Congress gave U.S. citizenship to Puerto Ricans when they were drafted to participate in World War I, as part of the Jones Act. Germany had miscalculated, believing it would be many more months before American soldiers would arrive and that their arrival could be stopped by U-boats.^[103]

The United States Navy sent a battleship group to Scapa Flow to join with the British Grand Fleet, destroyers to Queenstown, Ireland, and submarines to help guard convoys. Several regiments of U.S. Marines were also dispatched to France. The British and French wanted U.S. units used to reinforce their troops already on the battle lines and not waste scarce shipping on bringing over supplies. The U.S. rejected the first proposition and accepted the second. General John J. Pershing, American Expeditionary Forces (AEF) commander, refused to break up U.S. units to be used as reinforcements for British Empire and French units. As an exception, he did allow African-American combat regiments to be used in French divisions. The Harlem Hellfighters fought as part of the French 16th Division, earning a unit Croix de Guerre for their actions at Chateau-Thierry, Belleau Wood, and Sechault.^[104] AEF doctrine called for the use of frontal assaults, which had long since been discarded by British Empire and French commanders because of the large loss of life.^[105]

Austrian offer of separate peace[link]

In 1917, Emperor Charles I of Austria secretly attempted separate peace negotiations with Clemenceau, with his wife's brother Sixtus in Belgium as an intermediary, without the knowledge of Germany. When the negotiations failed, his attempt was revealed to Germany, resulting in a diplomatic catastrophe.^[106][107]

German Spring Offensive of 1918[link]

German General Erich Ludendorff drew up plans (codenamed Operation Michael) for the 1918 offensive on the Western Front. The Spring Offensive sought to divide the British and French forces with a series of feints and advances. The German leadership hoped to strike a decisive blow before significant U.S. forces arrived. The operation commenced on 21 March 1918 with an attack on British forces near Amiens. German forces achieved an unprecedented advance of 60 kilometres (37 mi).^[108]

British and French trenches were penetrated using novel infiltration tactics, also named Hutier tactics, after General Oskar von Hutier. Previously, attacks had been characterised by long artillery bombardments and massed assaults. However, in the Spring Offensive of 1918, Ludendorff used artillery only briefly and infiltrated small groups of infantry at weak points. They attacked command and logistics areas and bypassed points of serious resistance. More heavily armed infantry then destroyed these isolated positions. German success relied greatly on the element of surprise.^[109]

The front moved to within 120 kilometres (75 mi) of Paris. Three heavy Krupp railway guns fired 183 shells on the capital, causing many Parisians to flee. The initial offensive was so successful that Kaiser Wilhelm II declared 24 March a national holiday. Many Germans thought victory was near. After heavy fighting, however, the offensive was halted. Lacking tanks or motorised artillery, the Germans were unable to consolidate their gains. This situation was not helped by the supply lines now being stretched as a result of their advance.^[110] The sudden stop was also a result of the four Australian Imperial Force (AIF) divisions that were "rushed" down, thus doing what no other army had done: stopping the German advance in its tracks. During that time the first Australian division was hurriedly sent north again to stop the second German breakthrough.

British 55th (West Lancashire) Infantry Division troops blinded by tear gas during the Battle of Estaires, 10 April 1918.

General Foch pressed to use the arriving American troops as individual replacements. Pershing sought instead to field American units as an independent force. These units were assigned to the depleted French and British Empire commands on 28 March. A Supreme War Council of Allied forces was created at the Doullens Conference on 5 November 1917.^[111] General Foch was appointed as supreme commander of the allied forces. Haig, Petain, and Pershing retained tactical control of their respective armies; Foch assumed a coordinating rather than a directing role, and the British, French, and U.S. commands operated largely independently.^[111]

Following Operation Michael, Germany launched Operation Georgette against the northern English Channel ports. The Allies halted the drive after limited territorial gains by Germany. The German Army to the south then conducted Operations Blücher and Yorck, pushing broadly towards Paris. Operation Marne was launched on 15 July, attempting to encircle Reims and beginning the Second Battle of the Marne. The resulting counterattack, starting the Hundred Days Offensive, marked the first successful Allied offensive of the war.

By 20 July the Germans were back across the Marne at their Kaiserschlacht starting lines,^[112] having achieved nothing. Following this last phase of the war in the West, the German Army never regained the initiative. German casualties between March and April 1918 were 270,000, including many highly trained storm troopers.

Meanwhile, Germany was falling apart at home. Anti-war marches became frequent and morale in the army fell. Industrial output was 53 percent of 1913 levels.

New states under war zone[link]

In the late spring of 1918, three new states were formed in the South Caucasus: the Democratic Republic of Armenia, the Azerbaijan Democratic Republic, and the Democratic Republic of Georgia, which declared their independence from the Russian Empire.^[113] Two other minor entities were established, the Centrocaspian Dictatorship and South West Caucasian Republic (the former was liquidated by Azerbaijan in the autumn of 1918 and the latter by a joint Armenian-British task force in early 1919). With the withdrawal of the Russian armies from the Caucasus front in the winter of 1917–18, the three major republics braced for an imminent Ottoman advance, which commenced in the early months of 1918. Solidarity was briefly maintained when the Transcaucasian Federative Republic was created in the spring of 1918 but collapsed in May, when the Georgians asked and received protection from Germany and the Azerbaijanis concluded a treaty with the Ottoman Empire that was more akin to a military alliance. Armenia was left to fend for itself and struggled for five months against the threat of a full-fledged occupation by the Ottoman Turks.^[114]

Allied victory: summer and autumn 1918[link]

The Allied counteroffensive, known as the Hundred Days Offensive, began on 8 August 1918. The Battle of Amiens developed with III Corps British Fourth Army on the left, the French First Army on the right, and the Australian and Canadian Corps spearheading the offensive in the centre through Harbonnières.^[115][116] It involved 414 tanks of the Mark IV and Mark V type, and 120,000 men. They advanced 12 kilometres (7.5 mi) into German-held territory in just seven hours. Erich Ludendorff referred to this day as the "Black Day of the German army".^[115][117]

Aerial view of ruins of Vaux, France, 1918

The Australian-Canadian spearhead at Amiens, a battle that was the beginning of Germany's downfall,^[46] helped pull forward the British armies to the north and the French armies to the south. On the British Fourth Army front at Amiens, after an advance as far as 14 miles (23 km), German resistance stiffened, and the battle there concluded. But the French Third Army lengthened the Amiens front on 10 August, when it was thrown in on the right of the French First Army, and advanced 4 miles (6 km), liberating Lassigny in fighting which lasted until 16 August. South of the French Third Army, General Charles Mangin (The Butcher) drove his French Tenth Army forward at Soissons on 20 August to capture eight thousand prisoners, two hundred guns, and the Aisne heights overlooking and menacing the German position north of the Vesle.^[118] Another "Black day", as described by Erich Ludendorff.

Meanwhile General Byng of the British Third Army, reporting that the enemy on his front was thinning in a limited withdrawal, was ordered to attack with 200 tanks towards Bapaume, opening the Battle of Albert, with specific orders "To break the enemy's front, in order to outflank the enemy's present battle front" (opposite the British Fourth Army at Amiens).^[46] Allied leaders had now realised that to continue an attack after resistance had hardened was a waste of lives, and it was better to turn a line than to try to roll over it. They began to undertake attacks in quick order to take advantage of successful advances on the flanks, then broke them off when each attack lost its initial impetus.^[118]

The British Third Army's 15-mile (24 km) front north of Albert progressed after stalling for a day against the main resistance line to which the enemy had withdrawn.^[119] Rawlinson's British Fourth Army was able to push its left flank forward between Albert and the Somme, straightening the line between the advanced positions of the Third Army and the Amiens front, which resulted in recapturing Albert at the same time.^[118] On 26 August the British First Army on the left of the Third Army was drawn into the battle, extending it northward to beyond Arras. The Canadian Corps, already back in the vanguard of the First Army, fought its way from Arras eastward 5 miles (8 km) astride the heavily defended Arras-Cambrai area before reaching the outer defences of the Hindenburg Line, breaching them on the 28 and 29 August. Bapaume fell on 29 August to the New Zealand Division of the Third Army, and the Australians, still leading the advance of the Fourth Army, were again able to push forward at Amiens to take Peronne and Mont Saint-Quentin on 31 August. Further south, the French First and Third Armies had slowly fought forward while the Tenth Army, which had by now crossed the Ailette and was east of the Chemin des Dames, neared the Alberich position of the Hindenburg Line.^[120] During the last week of August the pressure along a 70-mile (113 km) front against the enemy was heavy and unrelenting. From German accounts, "Each day was spent in bloody fighting against an ever and again on-storming enemy, and nights passed without sleep in retirements to new lines."^[118] Even to the north in Flanders the British Second and Fifth Armies during August and September were able to make progress, taking prisoners and positions that had previously been denied them.^[120]

American troops in Vladivostok, Siberia, August 1918

Close-up view of an American major in the basket of an observation balloon flying over territory near front lines

On 2 September the Canadian Corps' outflanking of the Hindenburg line, with the breaching of the Wotan Position, made it possible for the Third Army to advance, which sent repercussions all along the Western Front. That same day Oberste Heeresleitung (OHL) had no choice but to issue orders to six armies to withdraw back into the Hindenburg Line in the south, behind the Canal du Nord on the Canadian-First Army's front and back to a line east of the Lys in the north. This ceded without a fight the salient seized the previous April.^[121] According to Ludendorff "We had to admit the necessity ...to withdraw the entire front from the Scarpe to the Vesle."^[122]

In nearly four weeks of fighting beginning 8 August, over 100,000 German prisoners were taken, 75,000 by the BEF and the rest by the French. As of "The Black Day of the German Army", the German High Command realised the war was lost and made attempts to reach a satisfactory end. The day after that battle Ludenforff told Colonel Mertz: "We cannot win the war any more, but we must not lose it either." On 11 August he offered his resignation to the Kaiser, who refused it, replying, "I see that we must strike a balance. We have nearly reached the limit of our powers of resistance. The war must be ended." On 13 August at Spa, Hindenburg, Ludendorff, the Chancellor, and Foreign Minister Hintz agreed that the war could not be ended militarily, and on the following day the German Crown Council decided that victory in the field was now most improbable. Austria and Hungary warned that they could only continue the war until December, and Ludendorff recommended immediate peace negotiations, to which the Kaiser responded by instructing Hintz to seek the mediation of the Queen of the Netherlands. Prince Rupprecht warned Prince Max of Baden: "Our military situation has deteriorated so rapidly that I no longer believe we can hold out over the winter; it is even possible that a catastrophe will come earlier." On 10 September Hindenburg urged peace moves to Emperor Charles of Austria, and Germany appealed to the Netherlands for mediation. On 14 September Austria sent a note to all belligerents and neutrals suggesting a meeting for peace talks on neutral soil, and on 15 September Germany made a peace offer to Belgium. Both peace offers were rejected, and on 24 September OHL informed the leaders in Berlin that armistice talks were inevitable.^[120]

September saw the Germans continuing to fight strong rear-guard actions and launching numerous counterattacks on lost positions, but only a few succeeded, and then only temporarily. Contested towns, villages, heights, and trenches in the screening positions and outposts of the Hindenburg Line continued to fall to the Allies, with the BEF alone taking 30,441 prisoners in the last week of September. Further small advances eastward would follow the Third Army's victory at Ivincourt on 12 September, the Fourth Army's at Epheny on 18 September, and the French gain of Essigny-le-Grand a day later. On 24 September a final assault by both the British and French on a 4-mile (6.4 km) front would come within 2 miles (3.2 km) of St. Quentin.^[120] With the outposts and preliminary defensive lines of the Siegfried and Alberich Positions eliminated, the Germans were now completely back in the Hindenburg Line. With the Wotan position of that line already breached and the Siegfried position in danger of being turned from the north, the time had now come for an Allied assault on the whole length of the line.

The Allied attack on the Hindenburg Line, begun on 26 September, included U.S. soldiers. The still-green American troops suffered problems coping with supply trains for large units on a difficult landscape.^[123] The following week cooperating French and American units broke through in Champagne at the Battle of Blanc Mont Ridge, forcing the Germans off the commanding heights, and closing towards the Belgian frontier.^[124] The last Belgian town to be liberated before the armistice was Ghent, which the Germans held as a pivot until the Allies brought up artillery.^[125][126] The German army had to shorten its front and use the Dutch frontier as an anchor to fight rear-guard actions.

Men of U.S. 64th Regiment, 7th Infantry Division, celebrate the news of the Armistice, 11 November 1918

When Bulgaria signed a separate armistice on 29 September, the Allies gained control of Serbia and Greece. Ludendorff, having been under great stress for months, suffered something similar to a breakdown. It was evident that Germany could no longer mount a successful defence.^[127][128]

Meanwhile, news of Germany's impending military defeat spread throughout the German armed forces. The threat of mutiny was rife. Admiral Reinhard Scheer and Ludendorff decided to launch a last attempt to restore the "valour" of the German Navy. Knowing the government of Prince Maximilian of Baden would veto any such action, Ludendorff decided not to inform him. Nonetheless, word of the impending assault reached sailors at Kiel. Many, refusing to be part of a naval offensive which they believed to be suicidal, rebelled and were arrested. Ludendorff took the blame; the Kaiser dismissed him on 26 October. The collapse of the Balkans meant that Germany was about to lose its main supplies of oil and food. Its reserves had been used up, even as U.S. troops kept arriving at the rate of 10,000 per day.^[129]

Having suffered over 6 million casualties, Germany moved towards peace. Prince Maximilian of Baden took charge of a new government as Chancellor of Germany to negotiate with the Allies. Telegraphic negotiations with President Wilson began immediately, in the vain hope that he would offer better terms than the British and French. Instead Wilson demanded the abdication of the Kaiser. There was no resistance when the Social Democrat Philipp Scheidemann on 9 November declared Germany to be a republic. Imperial Germany was dead; a new Germany had been born: the Weimar Republic.^[130]

Armistices and capitulations[link]

The signing of the armistice.

In the forest of Compiègne after agreeing to the armistice that ended the war, Foch is seen second from the right. The carriage seen in the background, where the armistice was signed, was later chosen as the symbolic setting of Pétain's June 1940 armistice. It was moved to Berlin as a prize, but because of Allied bombing was eventually moved to Crawinkel, Thuringia, where it was deliberately destroyed by SS troops in 1945.^[131]

The collapse of the Central Powers came swiftly. Bulgaria was the first to sign an armistice, on 29 September 1918 at Saloniki.^[132] On 30 October, the Ottoman Empire capitulated at Moudros (Armistice of Mudros).^[132]

On 24 October, the Italians began a push which rapidly recovered territory lost after the Battle of Caporetto. This culminated in the Battle of Vittorio Veneto, which marked the end of the Austro-Hungarian Army as an effective fighting force. The offensive also triggered the disintegration of the Austro-Hungarian Empire. During the last week of October, declarations of independence were made in Budapest, Prague, and Zagreb. On 29 October, the imperial authorities asked Italy for an armistice. But the Italians continued advancing, reaching Trento, Udine, and Trieste. On 3 November Austria–Hungary sent a flag of truce to ask for an Armistice. The terms, arranged by telegraph with the Allied Authorities in Paris, were communicated to the Austrian commander and accepted. The Armistice with Austria was signed in the Villa Giusti, near Padua, on 3 November. Austria and Hungary signed separate armistices following the overthrow of the Habsburg Monarchy.

Following the outbreak of the German Revolution of 1918–1919, a republic was proclaimed on 9 November. The Kaiser fled to the Netherlands. On 11 November an armistice with Germany was signed in a railroad carriage at Compiègne. At 11 am on 11 November 1918—"the eleventh hour of the eleventh day of the eleventh month"—a ceasefire came into effect. Opposing armies on the Western Front began to withdraw from their positions. Canadian Private George Lawrence Price was shot by a German sniper at 10:57 and died at 10:58.^[133] American Henry Gunther was killed 60 seconds before the armistice came into force while charging astonished German troops who were aware the Armistice was nearly upon them.^[134] The last British soldier to die was Pte George Edwin Ellison. The last casualty of the war was a German, Lieutenant Thomas, who, after 11 am, was walking towards the line to inform Americans who had not yet been informed of the Armistice that they would be vacating the buildings behind them.^[135] The occupation of the Rhineland took place following the Armistice. The occupying armies consisted of American, Belgian, British and French forces.

Allied superiority and the stab-in-the-back legend, November 1918[link]

In November 1918 the Allies had ample supplies of men and materiel to invade Germany. Yet at the time of the armistice, no Allied force had crossed the German frontier; the Western Front was still almost 900 mi (1,400 km) from Berlin; and the Kaiser's armies had retreated from the battlefield in good order. These factors enabled Hindenburg and other senior German leaders to spread the story that their armies had not really been defeated. This resulted in the stab-in-the-back legend,^[136][137] which attributed Germany's defeat not to its inability to continue fighting (even though up to a million soldiers were suffering from the 1918 flu pandemic and unfit to fight), but to the public's failure to respond to its "patriotic calling" and the supposed intentional sabotage of the war effort, particularly by Jews, Socialists, and Bolsheviks.

A formal state of war between the two sides persisted for another seven months, until the signing of the Treaty of Versailles with Germany on 28 June 1919. Later treaties with Austria, Hungary, Bulgaria, and the Ottoman Empire were signed. However, the negotiation of the latter treaty with the Ottoman Empire was followed by strife (the Turkish War of Independence), and a final peace treaty between the Allied Powers and the country that would shortly become the Republic of Turkey was not signed until 24 July 1923, at Lausanne.

Some war memorials date the end of the war as being when the Versailles Treaty was signed in 1919, which was when many of the troops serving abroad finally returned to their home countries; by contrast, most commemorations of the war's end concentrate on the armistice of 11 November 1918. Legally, the formal peace treaties were not complete until the last, the Treaty of Lausanne, was signed. Under its terms, the Allied forces divested Constantinople on 23 August 1923.

Technology[link]

Armoured cars