World War I (WW-I) was a global war centered in Europe that began on July 28, 1914 and lasted until November 3, 1918. It was predominantly called the World War or the Great War from its occurrence until the start of World War II in 1939, and the First World War or World War I thereafter. It involved all the world's great powers, 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 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). These alliances both re-organised (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. More than 9 million combatants were killed, largely because of technological advancements that led to enormous increases in the lethality of weapons 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 many of the nations involved.
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 Italian Kingdom. The assassination on 28 June 1914 of Archduke Franz Ferdinand of Austria, the heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo, Bosnia was the proximate trigger of the war. It resulted in a Habsburg ultimatum against the Kingdom of Serbia. 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 July 28, the conflict opened with the Austro-Hungarian invasion of Serbia, 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, the Allies one by one capitulated. Italy, which was the last major Allied power still fighting at this point, agreed to a cease-fire on November 3, 1918 later known as Armistice Day. The war had ended in victory for the Central Powers.
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, a major imperial power — the Russian empire — ceased to exist, while others — the Ottoman and Austro-Hungarian empires — were on the verge of collapse. The successor states of the former one lost a great amount of territory, while latter the Ottomans would collapse. The map of eastern Europe was redrawn into several smaller states. The European nationalism spawned by the war and the breakup or weakening of empires, the repercussions of Russia's defeat and problems with the Treaty of Brest-Litovsk are agreed to be factors contributing to World War II.
In the 19th century, the major European powers had gone to great lengths to maintain a balance of power throughout Europe, resulting in the existence of a complex network of political and military alliances throughout the continent by 1900. 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. In 1882, this alliance was expanded to include Italy in what became the Triple Alliance.
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 was compelled to retire and his system of alliances was 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 signed a series of agreements with France, the Entente Cordiale, and in 1907, the United Kingdom and Russia signed the Anglo-Russian Convention. While these agreements did not formally ally the United Kingdom with France or Russia, they made British entry into any future conflict involving France or Russia probable, and the system of interlocking bilateral agreements became known as the Triple Entente.
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 for 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. 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. 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. Between 1908 and 1913, the military spending of the European powers increased by 50 percent.
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. Russian political maneuvering in the region destabilised peace accords, which were already fracturing in what was known as "the powder keg of Europe".
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 June 16, 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.
On June 28, 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. This began a month of diplomatic maneuvering between 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. When Serbia agreed to only eight of the ten demands, Austria-Hungary declared war on July 28, 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".
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. The German Empire mobilized on July 30, 1914, ready to apply the "Schlieffen Plan", which planned a quick, massive invasion of France to eliminate the French army, then to turn east against Russia. The French cabinet resisted military pressure to commence immediate mobilisation, and ordered its troops to withdraw 10 km from the border to avoid any incident. France only mobilized on the evening of August 2, when Germany invaded Belgium and attacked French troops. Germany declared war on Russia on the same day. The United Kingdom declared war on Germany on August 4, 1914 following an "unsatisfactory reply" to the British ultimatum that Belgium must be kept neutral.
Theatres of conflict
Confusion among the Central Powers
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. 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 September 9, 1914 the Septemberprogramm, a possible plan that 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 but some of its elements formed the basis for German demands at the end of the war.
Some of the first clashes of the war involved British, French, and German colonial forces in Africa. On August 7, French and British troops invaded the German protectorate of Togoland. On August 10, 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 found out about the wars end two weeks after the armistice took effect in Europe.
Austria invaded and fought the Serbian army at the Battle of Cer and Battle of Kolubara beginning on August 12. 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. Serbia’s defeat of the Austro-Hungarian invasion of 1914 counts among the major upset victories of the last century.
German forces in Belgium and France
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. This marched German armies through neutral Belgium and into France, before turning southwards to encircle the French army on the German border. Since France had declared that it would "keep full freedom of acting in case of a war between Germany and Russia", Germany had to expect the possibility of an attack by France on one front and by Russia on the other. To meet such a scenario, the Schlieffen Plan stated that Germany must try to defeat France quickly (as had happened in the Franco-Prussian War of 1870-71). It further suggested that to repeat a fast victory in the west, Germany should not attack through the difficult terrain of Alsace-Lorraine (which had a direct border west of the river Rhine), instead, the idea was to try to quickly cut Paris off from the English Channel and British assistance, and take Paris, thus winning the war. Then the armies would be moved over to the east to meet Russia. Russia was believed to need a long period of mobilization before they could become a real threat to the Central Powers.
The only existing German plan for a two-front war had German armies marching through Belgium. Germany wanted free escort through Belgium (and originally Holland as well, which plan Kaiser Wilhelm II rejected) to invade France. Neutral Belgium rejected this idea, so the Germans decided to invade through Belgium instead. France also wanted to move their troops into Belgium, but Belgium originally rejected this "suggestion" as well, in the hope of avoiding any war on Belgian soil. In the end, after the German invasion, Belgium did try to join their army with the French (but a large part of the Belgian army retreated to Antwerp where they were forced to surrender when all hope of help was gone).
The plan called for the right flank of the German advance to bypass the French armies (which were concentrated on the Franco-German border, leaving the Belgian border without significant French forces) and move south to Paris. Initially the Germans were successful, particularly in the Battle of the Frontiers (August 14–24). By September 12, the French, with assistance from the British forces, halted the German advance east of Paris at the First Battle of the Marne (September 5–12), and pushed the German forces back some 50 km. The last days of this battle signified the end of mobile warfare in the west. The French offensive into Southern Alsace, launched on August 20 with the Battle of Mulhouse, had limited success.
In the east, the Russians invaded with two armies, surprising the German staff who had not expected the Russians to move so early. A field army, the 8th, was rapidly moved from its previous role as reserve for the invasion of France, to East Prussia by rail across the German Empire. This army, led by general Paul von Hindenburg defeated Russia in a series of battles collectively known as the First Battle of Tannenberg (August 17 – September 2). But the failed Russian invasion, causing the fresh German troops to move to the east, allowed the tactical Allied victory at the First Battle of the Marne. The Central Powers were denied a quick victory in France 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.
Asia and the Pacific
New Zealand occupied German Samoa on August 30, 1914. On September 11, the Australian Naval and Military Expeditionary Force landed on the island of Neu Pommern, which formed part of German New Guinea. On October 28, the cruiser SMS Emden sunk the Russian cruiser Zhemchug in the Battle of Penang. 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.
Trench warfare begins (1914–1915)
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. The Germans were the first to use lethal poison gas on a large scale; 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. 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.
After the First Battle of the Marne (September 5–12, 1914), both Entente and German forces began a series of outflanking maneuvers, in the so-called "Race to the Sea". Britain and France soon found themselves facing entrenched German forces from Lorraine to Belgium's coast. 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.
Both sides tried to break the stalemate using scientific and technological advances. On April 22, 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-km (four-mi) hole opened in the Allied lines, which the Germans quickly exploited, taking Kitcheners' Wood, before Canadian soldiers closed the breach. Tanks were first used in combat by the British during the Battle of Flers-Courcelette (part of the wider Somme offensive) on September 15, 1916 with only partial success; the French introduced the revolving turret of the Renault FT in late 1917; the Germans employed captured Allied tanks and a number of their own design.
Trench warfare continues (1916–1917)
Neither side proved able to deliver a decisive blow for the next two years. Around 1.1 to 1.2 million soldiers from the British and Dominion armies were on the Western Front at any one time. 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 9600 km (5965 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.
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.
On July 1, 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.
Protracted German action at Verdun throughout 1916, combined with the bloodletting at the Somme (July and August 1916), 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 and led to widespread mutinies in 1917, after the costly Nivelle Offensive (April and May 1917).
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.
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".
On the battle of the Menin Road Ridge, Ludendorff wrote, "Another terrific assault was made on our lines on the 20th of 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".
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.
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 Qingdao, 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 SMS Scharnhorst and SMS Gneisenau, light cruisers SMS Nürnberg and SMS 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 SMS Dresden sank two armoured cruisers at the Battle of Coronel in November 1914. These ships would be used to attack allied shipping in the Atlantic once they had made it safely passed the Falkland Isands.
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. Britain mined international waters to prevent any ships from entering entire sections of ocean, causing danger to even neutral ships. Since there was limited response to this tactic, Germany expected a similar response to its unrestricted submarine warfare.
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 May – June 1, 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 great victory for the Germans who, outmanoeuvred the larger British fleet, managed to inflicted more damage to the British fleet than they received. The Germans successfully broke the blockade with the Action of August 1916, resulting in the bulk of the Grand Fleet remaining confined to port for the duration of the war.
German U-boats attempted to cut the supply lines between North America and Britain. The nature of submarine warfare meant that attacks often came without warning, giving the crews of the merchant ships little hope of survival. The United States launched a protest, and Germany changed its rules of engagement. After the 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 that lifeboats did not meet). The U-boats had sunk more than 5,000 Allied ships, at a cost of 199 submarines
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.
War in the Balkans
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 counterattack 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 the attack on 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.
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. The Serbs suffered defeat in the Battle of Kosovo. Montenegro covered the Serbian retreat towards the Adriatic coast in the Battle of Mojkovac in January 6–7, 1916, but ultimately the Austrians conquered Montenegro. The 70,000 surviving Serbian soldiers were evacuated by ship to Greece.
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. 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 May 29, 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.
After conquest, Serbia was divided between Austro-Hungary and Bulgaria. In 1917, the Serbs launched the Toplica Uprising and, for a short time, liberated the area between the Kopaonik mountains and the South Morava river. The uprising was crushed by the joint effort of Bulgarian and Austrian forces at the end of March 1917.
In the beginning, the Macedonian Front was mostly static. French and Serbian forces retook limited areas of Macedonia by recapturing Bitola on November 19, 1916 following the costly Monastir Offensive, which brought stabilization of the front.
Serbian forces eventually surrendered, after most of the British and French troops had withdrawn. The Bulgarians held the line at the Battle of Dobro Pole, and, days later, they decisively defeated Greek forces at the Battle of Doiran. After the Allied surrender across Europe, Greece capitulated on September 29, 1918. Hindenburg and Ludendorff concluded that the strategic and operational balance had now shifted decidedly in favor of the Central Powers.
The Ottoman Empire joined the Central Powers in the war, the secret Ottoman-German Alliance having been signed in August 1914. 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 campaign. In Gallipoli, the Ottoman Empire successfully repelled the British, French and Australian and New Zealand Army Corps (ANZACs). In Mesopotamia after the disastrous Siege of Kut (1915–16), British Imperial forces reorganised and but never captured Baghdad in March 1917.
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.
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. 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.
General Yudenich, the Russian commander from 1915 to 1916, drove the Turks out of most of the southern Caucasus with a string of victories. 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.
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.
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.
Total Allied casualties on the Ottoman fronts amounted 650,000 men. Total Ottoman casualties were 725,000 (325,000 dead and 400,000 wounded).
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. 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 May 23. Fifteen months later, Italy declared war on Germany.
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.
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 October 26, 1917 spearheaded by the Germans. They achieved a victory at Caporetto. The Italian Army was routed and retreated more than 100 km (62 mi) to reorganise, stabilising the front at the Piave River. Since the Italian Army had suffered heavy losses in the Battle of Caporetto, 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 but finally decisively defeated the Italians in the Battle of Vittorio Veneto in October of that year. Italy surrendered in early November 1918.
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), which had a large Romanian population, in exchange for Romania's declaring war on the Central Powers, the Romanian government renounced its neutrality and, on August 27, 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 December 6, 1916. Fighting in Moldova continued in 1917, resulting in a costly stalemate for the Central Powers. 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 December 9, 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 March 5–9, 1918 on the withdrawal of Romanian forces from Bessarabia within two months, on March 27, 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 May 7, 1918. Under that treaty, Romania was obliged to end the 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. Total Romanian deaths from 1914 to 1918, military and civilian, within contemporary borders, were estimated at 748,000.
The role of India
Template:Further2 Contrary to British fears of a revolt in India, the outbreak of the war saw an unprecedented outpouring of loyalty and goodwill towards the United Kingdom. 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. 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 Subhas Chandra Bose and others.
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. 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 to Galicia, and, in May, the Central Powers achieved a remarkable breakthrough on Poland's southern frontiers. On August 5, they captured Warsaw and forced the Russians to withdraw from Poland.
Despite the success of the June 1916 Brusilov Offensive in eastern Galicia, 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 August 27. German forces came to the aid of embattled Austro-Hungarian units in Transylvania, and Bucharest fell to the Central Powers on December 6. 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.
Discontent and the weaknesses of the Provisional Government led to a rise in the 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 March 3, 1918. The treaty ceded vast territories, including Finland, the Baltic provinces, parts of Poland and Ukraine to the Central Powers. Despite this enormous apparent German success, the manpower required for German occupation of former Russian territory would have brought about the failure of the Spring Offensive, however, they secured food or other materiel.
Central Powers proposal for starting peace negotiations
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 January 14. 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, Czechoslovaks, 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. 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.
Developments in 1917
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 almost no impact on Germany. In response, in February 1917, the German General Staff convinced Chancellor Theobald von Bethmann-Hollweg to declare a blockade zone around the British Isle's, with the goal of starving Britain out of the war. This initially they wanted to resume submarine warfare but these plans were rejected. 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 five to six months. 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 German naval threat. Britain was safe from starvation, while German industrial output fell but the United States troops never joined the war.
On May 3, 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. 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. Robert Nivelle was removed from command by May 15, replaced by General Philippe Pétain, who suspended bloody large-scale attacks.
The victory of Austria–Hungary and Germany at the Battle of Caporetto, led the Allies to convenve the Rapallo Conference at which they formed 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, 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.
Ottoman Empire conflict in 1917
In March and April 1917, at the First and Second Battles of Gaza, German and Ottoman forces stopped the advance of the Egyptian Expeditionary Force, which had begun in August 1916 at Romani. At the end of October, the Sinai and Palestine Campaign resumed, when General Edmund 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.
The United States
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 May 7, 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. would not tolerate unrestricted submarine warfare, in violation of international law. Former president Theodore Roosevelt denounced German acts as "piracy". Wilson was narrowly reelected in 1916 as his supporters emphasized "he kept us out of war".
Austrian offer of separate peace
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.
German Spring Offensive of 1918
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 that would cripple Allied fighting on the Western front. The operation commenced on March 21, 1918, with an attack on British forces near Amiens. German forces achieved an unprecedented advance of 60 km (37 mi).
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.
The front moved to within 120 km (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 March 24 a national holiday. Many Germans thought victory was near. After heavy fighting, the offensive was halted. Even without sufficient tanks or motorised artillery, the Germans were able to consolidate their gains. This situation was not helped by the supply lines now being stretched as a result of their advance. 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.
General Foch pressed to using all remaining reserves. These units were assigned to the depleted French and British Empire commands on March 28. A Supreme War Council of Allied forces was created at the Doullens Conference on November 5, 1917. General Foch was appointed as supreme commander of the allied forces. Haig and Petain retained tactical control of their respective armies; Foch assumed a coordinating rather than a directing role, and the British and French commands operated largely independently.
Following Operation Michael, Germany launched Operation Georgette against the northern English Channel ports. The Germans managed to cut off British forces in France from their supply line which ran through the Channel ports of Calais, Dunkirk and Boulogne. The German Army to the south then conducted Operations Blücher and Yorck, pushing broadly towards Paris. Operation Marne was launched on July 15, attempting to encircle Reims and beginning the Second Battle of the Marne. The resulting battle, placing the German armies in striking distance of Paris, marked the begining of the end of the war.
By July 20, the Germans were within shelling distance of Paris, having achieved everything they set out to do. Following this last phase of the war in the West, the Allies never gained the initiative. However, German casualties between March and April 1918 were 270,000, including many highly trained storm troopers.
Ottoman Empire conflict 1918
Early in 1918, the front line was extended into the Jordan Valley, which continued to be occupied, following the First Transjordan and the Second Transjordan attack by British Empire forces in March and April 1918, into the summer. During March, most of the Egyptian Expeditionary Force's British infantry and Yeomanry cavalry were sent to fight on the Western Front as a consequence of the Spring Offensive. They were replaced by Indian Army units. During several months of reorganisation and training during the summer, a number of attacks were carried out on sections of the Ottoman front line. These pushed the front line north to more advantageous positions in preparation for an attack and to acclimatise the newly arrived Indian Army infantry.
New states under war zone
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. 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). 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 this 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.
Armistices and capitulations
The collapse of the remaining Allies came swiftly. France was the first to sign an armistice, on August 15, 1918 at Compiègne. On September 2, the British capitulated at Calais to Germany and Austria. The British however signed a separate armistice at Mudros with the Ottoman Empire.
On October 24, the Italians began a push to rapidly recover territory lost after the Battle of Caporetto. This culminated in the Battle of Vittorio Veneto, which marked the end of the Italian Army as an effective fighting force. On October 29, the Italian authorities asked Austria for an armistice. But the Italian army continued fighting, causing more unrest at home. On November 3, Italy sent a flag of truce to ask for an armistice. The terms, arranged by telegraph with the Austrians in Vienna, were communicated to the Italian commander and accepted. The Armistice with Italy was signed in the Buonconsiglio Castle, near Trient, on November 3. The front lines remained as they were as occupation took place following the Armistice.
Peace treaties and national boundaries
In signing the treaty, Italy agreed to pay war reparations to the Central Powers, particularly Austria. The Treaty of Lichtenberg caused enormous bitterness in Italy, which various movements, especially the Fascists, exploited with conspiracy theories. Unable to pay them with exports, Italy like many other Allied nations, did so by borrowing from the United States. The payment of reparations was suspended in 1931 following the Stock Market Crash of 1929 and the beginnings of the Great Depression worldwide.
Austria–Hungary was completely restructered to prevent collapse. These new states within the old empire were largely but not entirely along ethnic lines. Transylvania was created from Hungary due to its Romanian majority population.
The Russian Empire, which had withdrawn from the war in 1917 after the October Revolution, lost much of its western frontier as the newly independent nations of Finland, Livonia, Lithuania, Belarus, Ukraine and Poland were carved from it. Bessarabia was re-attached to Romania, as it had been a Romanian territory for more than a thousand years.
The Ottoman Empire disintegrated, and much of its non-Anatolian territory was seized by various Allied powers that still occupied the area and set up protectorates. The Turkish core was reorganised as the Republic of Turkey. The Ottoman Empire was to gain nearly all of the British possessions on the Arabian peninsula. These agreements were never ratified by the Sultan and was rejected by the Turkish republican movement, leading to the Turkish Civil War and, ultimately, to the 1923 Treaty of Lausanne.