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 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.