Italy, nominally allied with the German Empire and the Empire of Austria-Hungary in the Triple Alliance, in 1915 joined the Allies into World War I with a promise of substantial territorial gains, that included western Inner Carniola, former Austrian Littoral, Dalmatia as well as parts of the Ottoman Empire. The country gave a fundamental contribution to the victory of the conflict as one of the "Big Four" top Allied powers. The war on the Italian Front was initially inconclusive, as the Italian army got stuck in a long attrition war in the Alps, making little progress and suffering very heavy losses. However, the reorganization of the army and the conscription of the so-called "'99 Boys" ("Ragazzi del '99", all males born in 1899 who were turning 18) led to more effective Italian victories in major battles, such as on Monte Grappa and in a series of battles on the Piave river. Eventually, in October 1918, the Italians launched a massive offensive, culminating in the victory of Vittorio Veneto. The Italian victory, which was announced by the "Bollettino della Vittoria" and the "Bollettino della Vittoria Navale", marked the end of the war on the Italian Front, secured the dissolution of the Austro-Hungarian Empire and was chiefly instrumental in ending the First World War less than two weeks later. Italian armed forces were also involved in the African theatre, the Balkan theatre, the Middle Eastern theatre and then took part in the Occupation of Constantinople.