The Italian Regency of Carnaro (Reggenza Italiana del Carnaro), also known in Italian as Impresa di Fiume (Endeavour of Fiume), was a self-proclaimed state in the city of Fiume (now Rijeka, Croatia) led by Gabriele d'Annunzio between 1919 and 1920. During World War I (1914–1918), Italy made a pact with the Allies, the Treaty of London (1915), in which it was promised all of the Austrian Littoral, but not the city of Fiume. After the war, at the Paris Peace Conference, 1919, this delineation of territory was confirmed, with Fiume (or Rijeka) remaining outside of Italian borders and amalgamated into the Kingdom of Serbs, Croats and Slovenes. As a nationalist, Gabriele D'Annunzio was angered by what he considered to be the surrender of an Italian city. On 12 September 1919, he led a force that was about 2,600-strong and drawn mostly from former or serving members of the Granatieri di Sardegna brigade of the Royal Italian Army, as well as Italian nationalists and irredentists. Many members of D'Annunzio's force were reputedly veterans of the Battles of the Isonzo. They were successful in seizing control of the city, and forced the withdrawal of the Allied (US, British and French) occupying forces. The march from Ronchi dei Legionari to Fiume, by D'Annunzio's so-called "legionaries", became known as the Impresa di Fiume ("Fiume endeavor", or "Fiume enterprise"). On the same day, D'Annunzio announced that he had annexed the territory to the Kingdom of Italy. He was enthusiastically welcomed by the ethnic Italian portion of the population of Fiume. This was opposed by the Italian government, which attempted to pressure D'Annunzio to withdraw. The government initiated a blockade of Fiume and demanded that the plotters surrender. During his time in Fiume in September 1919, Filippo Tommaso Marinetti praised the leaders of the impresa as "advance guard deserters" (disertori in avanti). On December 8, the Italian government proposed a modus vivendi recognizing Fiume's desire for annexation and promising they would "only consider acceptable a solution consonant with that which Fiume declared to desire.