The Mountain War: World War I in the Austrian-Italian Alps
Italy had been allied with the German and Austro-Hungarian Empires since 1882 as part of the Triple Alliance. However, the nation had its own designs on Austrian territory in Trentino, the Austrian Littoral, Fiume (Rijeka) and Dalmatia. Rome had a secret 1902 pact with France, effectively nullifying its part in the Triple Alliance, offering parts of Austria (the Southern Tyrol, Austrian Littoral and territory on the Dalmatian coast) for participating in a war on their side.
The Italians had numerical superiority but this advantage was lost, not only because of the difficult terrain in which the fighting took place, but also because of the strategies and tactics employed. On the Trentino front, the Austro-Hungarians took advantage of the mountainous terrain, which favoured the defender. After an initial strategic retreat, the front remained largely unchanged, while Austrian Kaiserschützen and Standschützen engaged Italian Alpini in bitter hand-to-hand combat throughout the summer.
Beginning in 1915, the Italians under Cadorna mounted eleven offensives on the Isonzo front along the Isonzo (Soča) River, northeast of Trieste. All eleven offensives were repelled by the Austro-Hungarians, who held the higher ground. The Central Powers launched a crushing offensive on 26 October 1917, spearheaded by the Germans. They achieved a victory at Caporetto (Kobarid). The Italian Army was routed and retreated more than 100 kilometres (62 mi) to reorganise, stabilising the front at the Piave River.
On 1 November, the Armistice of Villa Giusti was signed. By mid-November 1918, the Italian military occupied the entire former Austrian Littoral and had seized control of the portion of Dalmatia that had been guaranteed to Italy by the London Pact.