Allies of World War I

• 1. Introduction

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  The Allies of World War I were an international military coalition that, by the war's end in 1918, represented roughly 70% of the world's population, 61% of its land, and 64% of its economic output. They called themselves the Entente, a French word meaning agreement, and the name stuck from a set of diplomatic arrangements made in the decade before the shooting started. The British, French, and Russians formed the core. Japan joined in August 1914. Italy switched sides in 1915. The United States arrived in 1917, the same year Russia left. By the time the Paris Peace Conference convened in 1919, the coalition had absorbed more than forty countries, dominions, colonies, and non-state forces, each with its own reasons for fighting.

  How did a network of colonial disputes and border rivalries transform into the largest military alliance the world had yet seen? Why did Italy abandon its treaty partners to join the other side? What made the United States enter as an "associated power" rather than a formal ally? And what happened to Serbia, the small kingdom whose invasion by Austria-Hungary lit the fuse? Those are the questions this documentary will answer.

• 2. Before the War

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  By the end of the first decade of the twentieth century, the major European powers had split into two blocs. The Triple Entente grouped the United Kingdom, France, and Russia together, while the Triple Alliance linked Germany, Austria-Hungary, and Italy. Neither arrangement was as solid as it appeared.

  Britain had spent most of the nineteenth century avoiding permanent alliances, a stance known as splendid isolation. That changed after the 1895-1905 Conservative government negotiated the 1902 Anglo-Japanese Alliance and then the 1904 Entente Cordiale with France. The 1905-1915 Liberal government extended the shift by concluding the 1907 Anglo-Russian Convention, which settled colonial disputes in Asia and let Britain redirect naval resources to the North Sea against Germany.

  France had its own reasons to seek allies. The 1870-1871 Franco-Prussian War had stripped France of Alsace-Lorraine and left it demographically weaker than Germany, whose 1911 population of 64.9 million dwarfed France's 39.6 million. France had the lowest birthrate in Europe, so when Germany let its Reinsurance Treaty with Russia lapse, France moved quickly to sign the 1894 Franco-Russian Alliance and became Russia's primary source of industrial financing.

  Russia in the late nineteenth century had been allied with Germany and Austria-Hungary through successive agreements, but competing interests in the Balkans broke both apart. By 1902, the Russian Empire had expanded to within 30 km of British India in some places, down from over 3,000 km in 1800. Defeat in the 1905 Russo-Japanese War shook Russia's confidence, but Tsar Nicholas approved a Russian Army expansion of over 500,000 men in 1913, and both Austria and Germany watched that growth with alarm.

  Italy's position was the most ambiguous of all. Its 1882 Triple Alliance with Germany and Austria-Hungary was renewed at regular intervals but undermined by a running dispute over Austrian-held territories that Italian nationalists called "the lost territories," including Istria, Trieste, Fiume, and Trento. The terms of the Alliance were kept secret until it expired in 1915, a sign of how controversial it had become.

• 3. How the Coalition Formed

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  Fighting began on the 28th of July 1914 when Austria invaded Serbia in response to the assassination of Archduke Franz Ferdinand, heir to Emperor Franz Joseph I. Montenegro entered the war on the 9th of August and attacked the Austrian naval base at Cattaro, now called Kotor. Russia, which had no formal alliance with Serbia but viewed itself as the protector of South Slavs, mobilised on the 30th of July; Germany declared war on Russia on the 1st of August, and Austria-Hungary followed on the 6th.

  Germany's entry into neutral Belgium on the morning of the 4th of August changed everything for Britain. Under Article VII of the 1839 Treaty of London, Britain had guaranteed Belgian neutrality and was obligated to defend it by force. Chancellor Theobald von Bethmann Hollweg dismissed that obligation as a "scrap of paper," but British law officers had consistently confirmed it as binding. The German high command knew entering Belgium would trigger British intervention and decided the risk was acceptable; they expected a short war, and their ambassador in London believed troubles in Ireland would prevent Britain from acting. They were wrong on both counts. Britain declared war on Germany on the 4th of August 1914, and that declaration automatically brought in all Dominions, colonies, and protectorates of the British Empire.

  Japan joined on the 23rd of August 1914, declaring war on Germany, and on Austria on the 25th of August. Japan's interest was straightforward: German territories in the Pacific and the Chinese province of Shandong. On the 2nd of September 1914, Japanese forces surrounded the German Treaty Port of Qingdao, then called Tsingtao, which surrendered on the 7th of November. The Imperial Japanese Navy simultaneously occupied German colonies in the Mariana, Caroline, and Marshall Islands.

  Italy stayed neutral in 1914 despite its Triple Alliance membership, with Prime Minister Antonio Salandra arguing the Alliance was defensive in nature and Austria's aggression against Serbia released Italy from its obligations. Alberto Pollio, the pro-Austrian Chief of Staff of the Italian Army, died on the 1st of July 1914, removing a key internal advocate for joining the Central Powers. Salandra described Italy's process of choosing sides as "sacred egoism." Under the April 1915 Treaty of London, Italy agreed to join the Entente in exchange for Italian-populated territories of Austria-Hungary; it declared war on Austria-Hungary in May 1915 but not on Germany until 1916.

  Ottoman warships bombarded Odessa in late October 1914, and the Entente declared war on the Ottoman Empire in November. After Germany declared war on Portugal in March 1916, Portugal joined the coalition. Romania commenced hostilities against Austria on the 27th of August 1916.

• 4. The American Entry

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  On the 6th of April 1917, the United States entered the war not as a formal ally but as a co-belligerent, and the distinction was deliberate. The US joined as an "associated power" to avoid what the government described as foreign entanglements, maintaining its legal and political distance from the older Entente arrangements even while fighting alongside them.

  Germany's unrestricted submarine warfare campaign in the Atlantic was the primary trigger, a direct violation of American neutral shipping rights. The Zimmermann Telegram added urgency: an intercepted German message that proposed helping Mexico regain territory it had lost to the United States nearly seven decades earlier in exchange for Mexican belligerence against the US. Neither the Ottoman Empire nor Bulgaria declared war on the United States, and Austria-Hungary did not do so immediately, but the US declared war on Austria-Hungary in December 1917, primarily to support a hard-pressed Italy.

  By the end of the war, the United States had mobilised roughly 4,355,000 personnel. Of those, 53,402 were killed in action, a fatality rate of roughly 1.23%, the lowest among the major Allied powers. The contrast with Serbia was stark: Serbia mobilised around 707,000 and suffered casualties amounting to 58% of that total, including over 275,000 military dead and, counting civilians and deaths from disease, more than 1.2 million deaths overall, close to 30% of the country's entire population.

  The same year the United States entered the war, Russia exited it. After the October Revolution in 1917, Russia left the Entente and signed the Treaty of Brest-Litovsk with the Central Powers on the 3rd of March 1918. Romania, left surrounded and without Russian support, was forced to sign a similar treaty in May 1918 but repudiated it on the 10th of November and declared war on the Central Powers again.

• 5. Smaller Allies, Larger Stakes

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  Serbia's position within the coalition was unlike any other member's. The kingdom had expanded its territory by 100% and its population by 64% following the 1913 Treaty of Bucharest that ended the Second Balkan War. But it now faced a hostile Austria-Hungary, a resentful Bulgaria, and resistance in its newly acquired territories. Germany also had ambitions along the Berlin-Baghdad railway corridor, and Serbia was the only section not controlled by a pro-German state.

  When Austria-Hungary invaded in 1914, Serbia initially held off the attack, but the country had been exhausted by two successive Balkan Wars and could not replace its losses. In 1915, Bulgaria joined the Central Powers and a combined Bulgarian-Austrian-German army occupied most of Serbia by year's end. The human cost was unmatched among the combatants: Serbia suffered the greatest proportional losses of any participant in the war.

  Greece presented a different kind of complexity. The assassination of King George I in 1913 brought to power his son Constantine, who had attended Heidelberg University, served in a Prussian regiment, and married Sophia of Prussia, the sister of Emperor William II. Constantine favoured the Central Powers. Prime Minister Eleftherios Venizelos favoured the Entente. That split produced what became known as the National Schism, with an Entente-backed administration under Venizelos operating in Crete and a Royalist government under Constantine in Athens. In October 1915, Venizelos allowed Entente forces to land at Thessaloniki to support Serbia, though they arrived too late to prevent the Serbian defeat. Constantine was forced into exile in June 1917, and Greece formally joined the Entente under a new national government led by Venizelos.

  Montenegro, which shared close cultural ties with Serbia, gained little from the 1912-1913 Balkan Wars and faced internal divisions between those who wanted independence and those who wanted union with Serbia. King Nicholas I of Montenegro seriously considered neutrality and even held discussions with Austria about staying out of the war entirely, but popular sentiment and military ties with Serbia made neutrality impossible. After declaring war on Austria-Hungary on the 1st of August 1914, the Montenegrin Army was eventually forced to surrender to an Austro-Hungarian force in January 1916.

  Romania entered in August 1916 on the condition of equal status with the main Entente powers, a recognition formalised in the 1916 Treaty of Bucharest. The Romanian campaign provided considerable relief to the Western Allies: Germany halted all other offensive operations to deal with Romania. When German prisoners were later captured by Romanian forces after the Battle of Mărășești in 1917, they reportedly told their captors that they "had not encountered such stiff resistance since the battles of Somme and Verdun."

• 6. Colonies and Non-State Forces

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  The coalition's manpower stretched far beyond the named nations. Over one million soldiers of the British Indian Army served across multiple theatres, primarily France and the Middle East. The five British Dominions, Australia, Canada, New Zealand, Newfoundland, and South Africa, all contributed significant forces. By 1918, the Australian Corps and the Canadian Corps in France were commanded by their own generals: John Monash and Arthur Currie respectively.

  France, facing a demographic shortfall compared to Germany, drew heavily on its colonial territories. Over 500,000 colonial troops served on the Western Front between 1914 and 1918, with others fighting at Gallipoli and in West Africa. In the Belgian Congo, 25,000 Congolese troops along with an estimated 260,000 porters joined British forces in the 1916 East African Campaign; by 1917 they controlled the western part of German East Africa, which later became the Belgian League of Nations Mandate of Ruanda-Urundi, the territory now known as Rwanda and Burundi.

  Three non-state combatants were permitted to participate as winning nations at the peace treaties. Armenian irregulars and volunteers, who had seceded from the Russian Empire after the revolution and fought the Ottoman Empire, were among them. So were Assyrian volunteers under Mar Shimun XIX Benyamin and Agha Petros of the Bit-Bazi tribe; the French offered these forces 20,000 rifles and the Assyrian army grew to 20,000 men. Polish Legions and Czechoslovak Legions, armed by France, Italy, and Russia, completed the group.

  The Idrisid Emirate of Asir, under its Emir Muhammad ibn Ali al-Idrisi, signed an agreement with Britain and joined the Allies in May 1915. The Emirate of Nejd and Hasa agreed to enter as a British ally through the Treaty of Darin on the 26th of December 1915. Brazil entered in 1917 after German unrestricted submarine warfare sank its merchant ships; the Brazilian Naval Division in War Operations joined the British fleet at Gibraltar, while a medical mission, military officers, and airmen served in France and with the Royal Air Force.

• 7. After the Armistice

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  The treaties negotiated at the Paris Peace Conference in 1919 recognised the British Empire, France, Italy, Japan, and the United States as the Principal Allied and Associated Powers. The first part of the Treaty of Versailles established the League of Nations, agreed on the 25th of January 1919 and brought into being on the 16th of January 1920, with Britain, France, Italy, and Japan as permanent members of its Executive Council.

  The United States, despite being one of the named Principal Powers, did not join the League. The US Senate voted against ratification of the treaty on the 19th of March, keeping the country out of the institution its own president had helped design.

  Italian resentment at the difference between what the April 1915 Treaty of London had promised and what the Versailles settlement actually delivered became one of the most consequential grievances in post-war European politics. Those unfulfilled promises would prove to be powerful factors in the rise of Benito Mussolini.

  New Guinea and German South West Africa, seized by Australia and South Africa respectively during the war, became Protectorates, held until 1975 and 1990. Japan, despite Allied protests, refused to return Qingdao and the province of Shandong to China after the war; the Twenty-One Demands Japan had imposed on China in January 1915, demanding extensive economic and political concessions, had already converted Japan from a partner into a perceived threat in the eyes of the other Allies. Greece did not receive the Dodecanese Islands from Italy until 1947, and some of the Aegean Islands remain disputed to this day.