World War I (WWI), which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centered in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world’s great powers, which were assembled in two opposing alliances: the Allies (centered on the Triple Entente of the United Kingdom, France and Russia) and the Central Powers (originally centered on the Triple Alliance of Germany, Austria-Hungary and Italy).
These alliances both reorganized (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 mobilized in one of the largest wars in history. More than 9 million combatants were killed, largely because of great technological advances in firepower without corresponding advances in 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.
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, France, 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 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 28 July, 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 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 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 of the Allies. By the war’s end, four major imperial powers—the German, Russian, Austro-Hungarian and Ottoman empires—had been militarily and politically defeated and 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.
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 generally agreed to be factors contributing to World War II. 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 9 September 1914, the September program, 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. Military tactics before World War I had failed to keep pace with advances in technology. These advances allowed for impressive defense 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 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 g as 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. 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 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 defenses. 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-kilometer (four-mile) hole opened in the Allied lines that the Germans quickly exploited, taking Kitchener’s’ Wood. Canadian soldiers closed the breach at the Second Battle of Ypres. At the Third Battle of Ypres, Canadian and ANZAC troops took the village of Passchendaele. 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 armored cruisers Scharnhorst and Gneisenau, light cruisers Nurnberg 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 armored 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 Mas a Tierra these too were destroyed or interned. 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 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, outmaneuvered 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. 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 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”. Finally, in early 1917 Germany adopted a policy of unrestricted submarine warfare, realizing the Americans would eventually enter the war.
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. 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. 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.
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, signaling 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 favor 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 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. 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. 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 Lusitania in 1915, with 128 Americans aboard, U. S. President Woodrow Wilson claimed 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 and U. S. ideas of human rights. Wilson was under pressure from former president Theodore Roosevelt, who denounced German acts as “piracy”.
Wilson’s desire to have a seat at negotiations at war’s end to advance the League of Nations also played a role in the eventual decision to join the war. Wilson’s Secretary of State, William Jennings Bryan, whose opinions had been ignored, resigned in 1915, as he could no longer support the president’s policy. Public opinion was angered at suspected German sabotage of Black Tom in Jersey City, New Jersey, and the Kingsland Explosion. In January 1917, Germany resumed unrestricted submarine warfare. The German Foreign Minister, in the Zimmermann Telegram, told Mexico that U. S. ntry was likely once unrestricted submarine warfare began, and invited Mexico to join the war as Germany’s ally against the United States. In return, the Germans would send Mexico money and help it recover the territories of Texas, New Mexico, and Arizona that Mexico had lost during the Mexican-American War 70 years earlier. Wilson released the Zimmerman note to the public, and Americans saw it as casus belli— a cause for war. After the sinking of seven U. S. merchant ships by submarines and the publication of the Zimmerman telegram, Wilson called for war on Germany, which the U. S. Congress declared on 6 April 1917.
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, 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.
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. 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. After the war, the Paris Peace Conference imposed a series of peace treaties on the Central Powers. The 1919 Treaty of Versailles officially ended the war.
Building on Wilson’s 14th point, the Treaty of Versailles also brought into being the League of Nations on 28 June 1919. In signing the treaty, Germany acknowledged responsibility for the war, and agreed to pay enormous war reparations and award territory to the victors. The “Guilt Thesis” became a controversial explanation of later events among analysts in Britain and the United States. The Treaty of Versailles caused enormous bitterness in Germany, which nationalist movements, especially the Nazis, exploited with a conspiracy theory they called the Dolchstosslegende (Stab-in-the-back legend).
The Weimar Republic lost the former colonial possessions and was saddled with accepting blame for the war, as well as paying punitive reparations for it. Unable to pay them with exports (as a result of territorial losses and postwar recession), Germany did so by borrowing from the United States. Runaway inflation in the 1920s contributed to the economic collapse of the Weimar Republic, and the payment of reparations was suspended in 1931 following the Stock Market Crash of 1929 and the beginnings of the Great Depression worldwide. U. S. intervention in the war, as well as the Wilson administration itself, became deeply unpopular.
This was reflected in the U. S. Senate’s rejection of the Versailles Treaty and membership in the League of Nations. In the interwar era, a consensus arose that U. S. intervention had been a mistake, and the Congress passed laws in an attempt to preserve U. S. neutrality in any future conflict. Polls taken in 1937 and the opening months of World War II established that nearly 60% regarded intervention in WWI as a mistake, with only 28% opposing that view. But, in the period between the fall of France and the attack on Pearl Harbor, public opinion changed dramatically and, for