The Treaty of London (Italian: Trattato di Londra; Russian: Лондонский договор, romanized: Londonskiy dogovor) or the Pact of London (Patto di Londra, French: Pacte de Londres) was a secret agreement concluded on 26 April 1915 by the United Kingdom, France, and Russia on the one part, and Italy on the other, in order to entice the latter to enter the Great War on the side of the Triple Entente. The agreement involved promises of Italian territorial expansion against Austria-Hungary, the Ottoman Empire and in Africa where it was promised enlargement of its colonies. The Entente countries hoped to force the Central Powers – particularly Germany and Austria-Hungary – to divert some of their forces away from existing battlefields. The Entente also hoped that Romania and Bulgaria would be encouraged to join them after Italy did the same.
In May 1915, Italy declared war on Austria-Hungary but waited a year before declaring war on Germany, leading France and the UK to resent the delay. At the Paris Peace Conference after the war, the United States of America applied pressure to void the treaty as contrary to the principle of self-determination. A new agreement produced at the conference reduced the territorial gains promised by the treaty: Italy received Trentino-Alto Adige/Südtirol and the Julian March in addition to the occupation of the city of Vlorë, Albania and the Dodecanese Islands. Italy was compelled to settle its eastern border with the new Kingdom of Serbs, Croats, and Slovenes through the bilateral Treaty of Rapallo. Italy thus received Istria and the city of Zadar as an enclave in Dalmatia, along with several islands along the eastern Adriatic Sea shore. The Entente went back on its promises to provide Italy with expanded colonies and a part of Asia Minor.
The results of the Paris Peace Conference transformed wartime national fervour in Italy into nationalistic resentment championed by Gabriele D'Annunzio by declaring that the outcome of Italy's war was a mutilated victory. He led a successful march of veterans and disgruntled soldiers to capture the port of Rijeka, which was claimed by Italy and denied by the Entente powers. The move became known as the Impresa di Fiume, and D'Annunzio proclaimed the short-lived Italian Regency of Carnaro in the city before being forced out by the Italian military so that the Free State of Fiume could be established instead. The Regency of Carnaro was significant in the development of Italian fascism.
Background
Soon after the outbreak of World War I, the Triple Entente powers – the United Kingdom, France, and Russia – sought to attract more allies to their side. The first attempt to bring in Italy (a part of the Triple Alliance) as an ally of the Entente was in August–September 1914. The matter became closely related to contemporary efforts to obtain an alliance with Bulgaria, or at least secure its neutrality, in return for territorial gains against Entente-allied Serbia. As compensation, Serbia was promised territories which were parts of Austria-Hungary at the time, specifically Bosnia and Herzegovina and an outlet to the Adriatic Sea in Dalmatia.
Negotiations
First offers
The August–September 1914 negotiations between the Entente and Italy were conducted on Russian initiative. On 4 August, only a day after Italy declared neutrality, its ambassador to Russia said that Italy might join the Entente in return for Trentino-Alto Adige/Südtirol, Vlorë, and a dominant position in the Adriatic. Believing that such a move by Italy would prompt Romania to join the Entente as well against Austria-Hungary, Russian foreign minister Sergey Sazonov pursued the matter. British Foreign Minister Edward Grey supported the idea; he said that Trieste should be added to the claim as potentially important to win over Italian public opinion on joining the war.
The Italian ambassador to the United Kingdom, Guglielmo Imperiali, presented Grey with Italy's conditions, but Grey did not consider the talks could produce any practical results. He told Imperiali that Britain would not consider the matter any further until Italy committed itself to joining the Entente. On Grey's instructions, Rennell Rodd, British ambassador to Italy, asked Italian Prime Minister Antonio Salandra if Italy could enter the war. Salandra informed Rodd that this was impossible at the time and that any premature attempt to abandon neutrality would jeopardise any prospect of a future alliance. Sazonov was informed accordingly, and Russia abandoned the matter.
The motives for the Entente's overture to Italy and Italian consideration of entering the war were entirely opportunistic. The Entente saw Germany as the principal enemy and wanted to force it to divert some of its forces away from the existing battlefields. Italy had basically different interests from the Entente powers. It saw opportunities to fulfil Italian irredentist objectives in Austria-Hungary, to gain a dominant position in the Adriatic basin and to expand its colonial empire. Initially, the majority of the Italian public favoured neutrality, but groups favouring an expansionist war against Austria-Hungary formed in every part of the political spectrum. The most ardent supporters of war became irredentist groups such as Trento e Trieste (Trento and Trieste) led by Giovanni Giuriati or Alfredo Rocco who saw the war as an opportunity for ethnic struggle against neighbouring South Slavic populations.
Occupation of Vlorë
Salandra and his foreign minister Antonino Paternò Castello did not break off the negotiations completely. They used the subsequent months to wait for a chance to increase Italian demands to the maximum at an opportune time. There was an attempt to relaunch the negotiations in London on 16 September when Castello told Rodd that the British and Italians shared interests in preventing westward spread of Slavic domains under Russian influence, specifically by preventing Slavic influence in the Adriatic, where irredentists claimed Dalmatia. While Castello instructed Imperiali to tell the British that Italy would not decide to abandon its neutrality before the Entente accepted their conditions, Grey insisted on Italy first committing to joining the Entente and the talks collapsed again.
Particular opposition to the Italian claim against Dalmatia came from the Permanent Under-Secretary of State for Foreign Affairs Arthur Nicolson who remarked that Sazonov was right to claim that Dalmatia wished to unite with Kingdom of Croatia-Slavonia. He added that if Dalmatia were annexed by Italy, it would inherit a problem from Austria-Hungary, that of having a large South Slavic population looking for greater independence.
Nonetheless, Castello managed to obtain British endorsement for Italian occupation of Vlorë. The move was made as a preparation for Italian intervention and designed to lend some prestige to the Italian government. Expecting opposition from Sazonov, Castello asked Grey to get the Russians to let him have this without making any concessions in return as a necessary evil to attract Italy to join the Entente.
Sonnino replaces Castello
In late October, there was an attempt to get Italy to intervene against an expected Turkish attack against the Suez Canal. Sazonov warned Grey not to offer Dalmatia in exchange and the latter replied that no such offer was made as the canal remaining open was in Italian interests too.
The matter of an Italian alliance was taken up by Castello's successor Sidney Sonnino and Rodd in November. Sonnino proposed a non-binding agreement which could be turned into a binding one at an opportune time. Even though similar proposals by his predecessor were turned down, Rodd was informed through his contacts in the Italian government that the Italian Armed Forces were prepared to intervene by February 1915, prompting Rodd to urge Grey to consider the proposal. However, Grey declined the idea as a hypothetical bargain as he appeared indifferent to an Italian alliance at this point.
Following this, Salandra and Sonnino conducted negotiations with the Central Powers in an apparent attempt to keep the Central Powers at bay until further negotiations were possible with the Entente. These talks collapsed on 15 February 1915. The following day, Sonnino sent Imperiali a specific list of conditions set out in sixteen points necessary for Italy to enter the war.
Seeking Bulgarian alliance
While the Entente Powers were negotiating with Italy, they led a concurrent diplomatic effort aimed at obtaining Bulgarian alliance (or at least friendly neutrality). This situation led to a conflict of territorial claims staked by Italy and Serbia. Namely, awarding Italy Dalmatia would largely block the Adriatic outlet offered to Serbia (in addition to Bosnia and Herzegovina) as compensation to Serbia's cession of much of Vardar Macedonia to Bulgaria requested by the Entente as enticement to Bulgaria. Sazonov wanted to strengthen his offer to Serbia and indirectly to Bulgaria by guaranteeing such an outlet to Serbia, but Grey blocked the initiative, arguing that an Italian alliance was more important.
In mid-February, following the start of the Gallipoli campaign, the British were convinced that Bulgaria would enter the war on the side of the Entente within weeks, certain of its victory. Even though it worked to bring Bulgaria on board, Russia was anxious that Bulgarian and Greek forces might occupy Constantinople to push Russia out of the region despite being promised control of the city by the Entente. Sonnino saw the combined Bulgarian and Greek entry into the war likely to assure Entente victory in the Balkans. On 4 March, Imperiali informed Grey that Italy would enter the war and presented him with the 16 conditions insisting on curtailing Slavic westward advance.
Russian claim over Constantinople
Grey noted that the Italian claims were excessive, but also that they did not conflict with British interests. He also thought that recent Russian stubborn objections against Greek attack to capture Constantinople could be overcome by addition of Italian troops, and that Italian participation in the war would expedite a decision from Bulgaria and Romania, still waiting to commit to the war.
Sazonov objected to any Italian role regarding Constantinople, seeing it as a threat to Russian control of the city promised by the allies in return for Russian losses in the war. This led Grey to obtain formal recognition of the Russian claim to the city by the Committee of Imperial Defence and by France, leading Sazonov to acquiesce to an agreement with Italy, except he would not consent to Italy taking the Adriatic coast south of the city of Split and as long as the Italian troops did not participate in the capture of the Turkish Straits.
The request concerning the Turkish Straits was found acceptable by Grey since the British never anticipated Italy would take part in the campaign against Constantinople. The bulk of the Italian claim, concerning acquisition of Trentino, Trieste, and Istria was likely to attract protests against handing predominantly Slav-populated territories to Italy from Frano Supilo – a dominant figure in the nascent Yugoslav Committee advocating interests of South Slavs living in Austria-Hungary. On the other hand, the Serbian Prime Minister Nikola Pašić and Sazonov found it acceptable. Even though Serbian Niš Declaration of war objectives called for the struggle to liberate and unify "unliberated brothers", referring to "three tribes of one people" meaning the Serbs, the Croats, and the Slovenes, as means to attract support from South Slavs living in Austria-Hungary, Pašić was primarily concerned with achieving a Greater Serbia. Sazonov acquiesced, adding that he has nothing to say on behalf of the Croats and the Slovenes and would not approve Russian forces to fight "half a day" for liberty of the Slovenes.
Final six weeks of talks
Nonetheless, negotiations extended for six weeks over disagreements as the extent of Italian territorial gains in Dalmatia was still objected to by Sazonov. The Italian claim of Dalmatia to the Neretva River, including the Pelješac Peninsula and all Adriatic islands was not based on self-determination, but on security concerns in a future war, as the Italian negotiators alleged that Russia might occupy the Austrian-controlled coast while Italy had no defensible port on the western shore of the Adriatic. The Committee of Imperial Defence was concerned about rising Russian naval power in the Mediterranean and it is possible, although there is no direct evidence, that this influenced the British support for the Italian claims in the Adriatic, as means to deny it to Russia.
Hoping to achieve the diplomatic breakthrough in securing alliances with Bulgaria, Romania, and Greece, Grey turned Sonnino's 16 points into a draft agreement and forwarded it to Russia against protests by the Yugoslav Committee. Sazonov objected to the draft agreement and dismissed an Italian offer of Dubrovnik as a port for South Slavs as it lacked inland transport routes. Sazonov demanded Split in addition as a better port and objected to the requested demilitarisation of the coast belonging to the Kingdom of Montenegro. Grey drew up a document taking into consideration the Russian objections and forwarded it to Imperiali, but Sonnino threatened to end the negotiations over the differences.