January 18 – The Paris Peace Conference opens. Prime Minister Vittorio Emanuele Orlando is one of the Big Four, the main Allied leaders and participants at the Paris Peace Conference in 1919, along with U.S. President Woodrow Wilson, French Prime Minister Georges Clemenceau and Britain's Prime Minister David Lloyd George.[1] The Italian delegation demands the fulfilment of the "secret Treaty of London of 1915, by which the Allies had promised Italy ample territorial compensation in Dalmatia for its entry into World War I."[2] Although, as prime minister, Orlando was the head of the Italian delegation, his inability to speak English and his weak political position at home allowed the conservative Foreign Minister, Sidney Sonnino, to play a dominant role.[3] Their differences proved to be disastrous during the negotiations. Orlando was prepared to renounce territorial claims for Dalmatia to annex Rijeka (or Fiume as the Italians called the town) - the principal seaport on the Adriatic Sea - while Sonnino was not prepared to give up Dalmatia. Italy ended up claiming both and got none, running up against Wilson's policy of national self-determination.[4]
April 15 – U.S. President Woodrow Wilson issues a memorandum proposing a line, the so-called "Wilson Line", dividing the Istrian peninsula between Italy and Yugoslavia. Trieste and Pula, with the railway connecting them, lay on the Italian side; Fiume and Ljubljana, with the railway connecting them, on the Yugoslav. Učka (Monte Maggiore) was to be Italian, but the Wilson Line ran further west of Fiume than that of the Treaty of London. Italy would have none of the rights in northern Dalmatia granted it by that treaty, but it would receive the islands of Vis (Lissa) and Lošinj (Lussin).[4][7] After the resignation of Orlando and Sonnino in June, the new Foreign Minister Tommaso Tittoni alters the course of negotiations by abandoning the Treaty of London and strengthening the Franco-Italian alliance, but he did not accept President Wilson's proposed "line". The French diplomat André Tardieu worked as an intermediary between Tittoni and the Americans, and he first suggested the creation of a buffer state out of a strip of land around Fiume, the future Free State of Fiume.[7]
April 26 – Fiume affair. Faced with the refusal of Wilson, Clemenceau and Lloyd George to assign Fiume to Italy, Orlando abandons the Paris Peace Conference and returns to Rome.
June 19 – Prime Minister Vittorio Emanuele Orlando resigns following his inability to acquire Fiume for Italy in the peace settlement.[4] On June 23, he is succeeded by Francesco Saverio Nitti. His cabinet has to deal with great social unrest and dissatisfaction over the results of the Treaty of Versailles. Particularly troublesome was the agitation over Fiume led by Gabriele D'Annunzio. Nitti had great difficulty keeping the administration functioning at all, thanks to the enmity between the extremely divergent political factions.
September 12 – The nationalist poet Gabriele D’Annunzio leads 2,600 Italian irredentist troops against a mixed force of Allied soldiers to occupy the city of Fiume.[12][13] The march to Fiume became known as the Impresa di Fiume ("Fiume Exploit"). D'Annunzio announces that he had annexed the territory to the Kingdom of Italy. He was enthusiastically welcomed by the Italian population of Fiume. The move was opposed by the Italian government, and D'Annunzio tried to resist pressure from Italy. The plotters sought to have Italy annex Fiume, but this was denied. Instead, Italy initiated a blockade of Fiume while demanding that the plotters surrender.[14] The victors establish the Italian Regency of Carnaro, an unrecognized state based on the proto-fascist Charter of Carnaro.
September 29 – The Italian parliament is dissolved after Foreign Minister Tittoni withdraws and fights erupt in the Chamber of Deputies during the debate about the annexation of Fiume, opposed by Prime Minister Nitti. Elections are set for November 16.[15] For the first time, Catholics are allowed to vote on their own candidates of the Italian People's Party.[16]
^Cfr. Gabriele D'Annunzio, in an editorial in Corriere della Sera, October 24, 1918, Vittoria nostra, non sarai mutilata ("Our victory will not be mutilated").