Treaty of London (1915)

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For other Treaties of London see Treaty of London (disambiguation).
Treaty of London
TypeBilateral treaty
Signed26 April 1915 (1915-04-26)
LocationLondon, England, United Kingdom
Flag of the United Kingdom.svg  United Kingdom
Flag of France (1794-1815, 1830-1958).svg France
Flag of The Russian Empire 1883.svg  Russia
Flag of Italy (1861-1946) crowned.svg  Italy

The Treaty of London (Italian : Trattato di Londra), or, less correctly, the Pact of London ('Patto di Londra), was a secret treaty between the Triple Entente and the Kingdom of Italy that brought Italy into World War I on the Allied side. It was signed in London on 26 April 1915 by Great Britain, France, Russia, and Italy. [1] Its intent was to have Italy break away from its 33-year-old Triple Alliance with the German Empire and Austria-Hungary, both the main Central Powers in the war, and to switch its allegiance to the Triple Entente, the main Allies in the war. The main lure for Italy was a promise of large amounts of Austria-Hungary to the north of Italy and to the east across the Adriatic and the promise of funding by Britain. Italy, which had remained neutral for the first nine months of the war, promised to enter the war within a month.


The Triple Alliance had never been popular with the 36 million Italians and had more recently been promoted by some politicians for realpolitik. Many provisions of the Treaty of London were meant to be kept secret for the rest of the war, but they were published by the Bolsheviks after they had come to power in Russia in late 1917.

After the war ended, both British and French leaders refused to fulfil the treaty. That rose to a belief in a so-called "mutilated victory" in Italy that played a role in determining Italy's interwar expansion, fueled the rhetoric of irredentism and Italian nationalism before World War II and was a key reason for the rise of Italian Fascism.


The Italian minister of foreign affairs made it plain to the Austro-Hungarian ambassador that Italy would not fight with Germany and Austria but also that compensation was expected for Austria-Hungary's extension of its territory into Serbia. For six months, Italy remained neutral and stated that the Triple Alliance was defensive and that no alliance member should have declared any act of war without previous consultation of the other treaty signatories. Article 7 of the Alliance foresaw compensation to maintain the balance of power in the Balkans. Austria-Hungary had consulted only Germany in the days before the ultimatum to Serbia, and Italy discovered the Austro-Hungarian declaration of war by the newspapers, rather than the ambassadors. Italy took the initiative in entering the war in the spring 1915, despite strong support by both the ordinary people and the elite for neutrality. Italy was a poor country whose political system was chaotic, finances were heavily strained, and army was very poorly prepared. [2] The Triple Alliance had meant little to Italy or Austria-Hungary since Vienna had declared war on Serbia without consulting Rome. Two men, Prime Minister Antonio Salandra and Foreign Minister Sidney Sonnino made all the decisions in Italy, as was typical in its foreign policy. They operated in secret by enlisting the king later on but keeping military and political leaders entirely in the dark. They negotiated with both sides for the better deal, which they obtained from the Entente, which was quite willing to promise large slices of Austria-Hungary, including the Tyrol as well as Trieste. Russia vetoed giving Dalmatia and Albania to Italy. Britain was willing to pay to have 36 million Italians as new allies to threaten the southern flank of Austria. [3]

Only after the treaty was secretly signed in April 1915, the antiwar leader Giolitti collected enough parliamentary support to force Prime Minister Salandra to resign. While he consulted the king to establish a new government, Giolitti was informed that Italy was already committed to war and faced the choice of acquiescing or risking a crisis between Parliament and the King and another between Italy and the treaty's other signatories. Giolitti let Salandra return to office. Most politicians, Catholics and other Italians opposed the war. Reports from around Italy showed the people both feared war and cared little about territorial gains. Rural folk saw war as a disaster, like drought, famine or plague. Businessmen generally opposed the war for fear of heavy-handed government controls and taxes and loss of foreign markets. Reversing the decision seemed impossible since the Triple Alliance did not want Italy back, and the King's throne was at risk. Pro-war supporters mobbed the streets with tens of thousands of shouting by nationalists, Futurists, anticlericals, and angry young men. Benito Mussolini, an important Socialist Party editor, took a leadership role, but he was expelled from the party by state, and only a pro-war minority followed him. Apart from Russia, it was the only leftist political party in Europe that openly opposed the war. The fervour for war represented a bitterly-hostile reaction against politics as usual and the failures, frustrations, and stupidities of the ruling class. [4] [5]


According to the treaty, Italy was to leave the Triple Alliance and to join the Triple Entente. Italy was to declare war against the German Empire and Austria-Hungary within a month (Italy declared war against Austria-Hungary within a month but not against the German Empire until a year later, on August 27, 1916 [6] ). Assuming its victory against Germany and its allies, the Triple Entente promised Italy the following territorial gains after the war (see Italia irredenta ):

Tyrol, partitioned in 1918, had parts that remained under the control of Austria and referred to as Nordtirol and Osttirol but were part of the Federal State of Tyrol. Tirol-Suedtirol-Trentino.png
Tyrol, partitioned in 1918, had parts that remained under the control of Austria and referred to as Nordtirol and Osttirol but were part of the Federal State of Tyrol.
Territories promised to Italy by the Entente on the Eastern Adriatic, in the Austrian Littoral and in Dalmatia TratadoDeLondresTerritoriosParaItalia.svg
Territories promised to Italy by the Entente on the Eastern Adriatic, in the Austrian Littoral and in Dalmatia
Territories promised to Serbia and Montenegro by the Triple Entente Trattato di Londra.svg
Territories promised to Serbia and Montenegro by the Triple Entente
  1. Tyrol, up to the Alpine water divide at the Brenner Pass, which includes the what is now the Italian provinces of Trentino and Alto Adige (the latter being called "Cisalpine Tyrol"). [7]
  2. The entire Austrian Littoral, including Istria, the port of Trieste and the Cres-Lošinj archipelago but without the island of Krk (Veglia) and the Hungarian port of Rijeka.
  3. Northern Dalmatia, including Zadar, Šibenik and most of the Dalmatian islands except Rab and Brač.
  4. The districts of Vipava, Idrija and Ilirska Bistrica, in the Austrian Duchy of Carniola.
  5. The townships of Pontebba (Pontafel) and Malborghetto Valbruna (Malborgeth-Wolfsbach) in the Austrian Duchy of Carinthia.
  6. The Dodecanese Islands, held by Italy since 1912
  7. The port of Vlorë, in Albania
  8. A protectorate over Albania ("Italy should be entrusted with the task of representing the State of Albania in its relations with Foreign Powers")
  9. Small compensations in Africa if German colonies in Asia and Africa were occupied by Allies, [8] particularly border adjustments between the existing Italian colonies and the British and French colonies.
  10. In the event of the partition of Ottoman Empire, Italy "ought to obtain a just share of the Mediterranean region adjacent to the province of Adalia" [8]
Vilayet of Adalia (Antalya), allotted to Italy Vilayet of Adalia (Antalya) in 1890.png
Vilayet of Adalia (Antalya), allotted to Italy

The Kingdom of Serbia, which was not present nor a signatory, was assigned:

  1. The Dalmatian Coast between the Krka and Stagno (Ston), including the Sabbioncello Peninsula (Pelješac), the port of Split, and the island of Brazza (Brač).

The Kingdom of Montenegro, which was not present nor a signatory, was assigned:

  1. The Dalmatian Coast between Budua (Budva) and Stagno (Ston), including Ragusa (Dubrovnik) and Bocche di Cattaro (Boka Kotorska) but without the Sabbioncello (Pelješac) peninsula;
  2. The coast south to the Albanian port of Shengjin (San Giovanni di Medua).

Also, but less precisely, Serbia was assigned[ citation needed ]:

  1. Bosnia and Herzegovina
  2. Syrmia
  3. Bačka
  4. Slavonia (against Italian objections)
  5. Some unspecified areas of Albania (to be divided among Serbia, Montenegro, and Greece).

Italy insisted and the Allies agrees that the Adriatic Question, between Zara and Istria, should be settled after the war. Italy also insisted that Serbia should not be informed about the agreements. However, the Allies overruled that by sending an official note to Serbia on 4 August 1915, which confirmed the postwar territorial claims of Serbia and Montenegro.

The treaty was to be kept secret, but after the Bolshevik Revolution in Russia, it was published in November 1917 by the Russian Bolshevik journal Izvestia .

Paris Peace Conference

After the war, Italy would negotiate only with Serbia and Montenegro. The Italian delegation staged a walkout for a number of months after it had been faced with the denial of its territorial demands.[ citation needed ]

The treaty was nullified by the Treaty of Versailles. Before 1918, the contents of the treaty had been published by Bolshevik writers. The Fourteen Points, as proposed by US President Woodrow Wilson, contained a number of clauses that argued for ethnic or national self-determination and against the provisions of the Treaty of London:

Wilson believed that since the Treaty of London had been arrived at by secret contract, it was not valid although he had no particular problem with the implementation of other secret wartime agreements, such as the Sykes–Picot Agreement. Overall, Wilson sought to achieve borders that were determined by the populations in the area, rather than by outside parties. Also, the Treaty of London gave Italy areas whose populations were not mostly Italian. Wilson believed that Slavic claims to some of the disputed regions were more sound than Italian claims. [9]

Ultimately, Italy was denied other gains promised in the treaty, such as a share of German colonies and the control of Albania. [8] Italy tried to establish a physical claim in Anatolia, Turkey, but was quickly forced to evacuate. The partition of Tyrol on the water divide line, against the wishes of its mostly-German population, was confirmed by the Treaty of Saint-Germain.


Residents of Fiume cheering the arrival of Gabriele d'Annunzio and his blackshirt-wearing nationalist raiders, as D'Annunzio and Fascist Alceste De Ambris developed the quasi-fascist Italian Regency of Carnaro, a city-state in Fiume, from 1919 to 1920 and whose actions by D'Annunzio in Fiume inspired Italian Fascists Fiume cheering D'Annunzio.jpg
Residents of Fiume cheering the arrival of Gabriele d'Annunzio and his blackshirt-wearing nationalist raiders, as D'Annunzio and Fascist Alceste De Ambris developed the quasi-fascist Italian Regency of Carnaro, a city-state in Fiume, from 1919 to 1920 and whose actions by D'Annunzio in Fiume inspired Italian Fascists

After the war, British and French leaders refused to follow through on the stipulations of the treaty. Irredentist nationalist element of Italy considered that to be an inexcusable betrayal by both European allies. The colonial gains by Britain and France from the war further angered the Italians who felt excluded, although both powers' gains had been largely in the form of mandates from the League of Nations to prepare for independence, rather than simple colonial expansion.

The breakdown of the pact helped give rise to the Italian belief in a so-called "mutilated victory", which played a role in determining Italian interwar expansion. In 1920, Italian nationalists created the Free State of Fiume although it had not been assigned to Italy in the Treaty of London. That underscored the unstable results of the Treaty of Versailles concerning Italian claims.

During negotiations, the United States suggested for the pact to be revised on the grounds of a fundamental change in circumstances. Though that reasoning was rejected by the other powers, it is noteworthy as an early example of American invocation of that legal principle. [10]

See also

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  1. Ray Stannard Baker, Woodrow Wilson and World Settlement, Volume I, Doubleday, Page, and Company, 1923, pp. 52–55
  2. William A. Renzi, In the Shadow of the Sword: Italy's Neutrality and Entrance Into the Great War, 1914–1915 (1987).
  3. C.J. Lowe, "Britain and Italian Intervention 1914-1915." Historical Journal (1969) 12#3, pp. 533-48.
  4. Martin Clark, Modern Italy: 1871-1995 (1996), pp. 180-5.
  5. Denis Mack Smith, Italy: A Modern History (1969), pp. 292–305.
  6. "The Italian Declaration of Neutrality - World War I Document Archive". Retrieved 2018-04-19.
  7. Moos, Carlo (2017), "Südtirol im St. Germain-Kontext", in Georg Grote and Hannes Obermair (ed.), A Land on the Threshold. South Tyrolean Transformations, 1915–2015, Oxford-Berne-New York: Peter Lang, pp. 27–39, ISBN   978-3-0343-2240-9
  8. 1 2 3 "First World - Primary Documents - Treaty of London, 26 April 1915". Retrieved 2019-07-11.
  9. American Society of International Law. Volume 15, Oxford University Press, 1921, p. 253.
  10. Mahmood M. Poonja, Termination of Treaties Owing to Fundamental Change of Circumstances (Clausula Rebus Sic Stantibus): A Doctoral Dissertation [Juris Doctor dissertation, Charles University, Prague, 1977] (Rawalpindi: Abbas Arts, 1982), p. 19.

Further reading