The Battle of Vittorio Veneto was the last battle of the Italian Front during World War One. It was a decisive victory for the Italian forces, who managed to cause the collapse of the Austro-Hungarian army. The Italian victory contributed to the end of the war, less than 2 weeks later, and caused the dissolution of the Austro-Hungarian Empire at the end of the war.
In the spring and summer, French Marshal Ferdinand Foch asked Diaz to support the operations in France by attacking across the Piave. Diaz refused: his army was not ready. Orlando agreed, but changed his mind by mid-September when it became clear that the Entente breach of the Hindenburg Line meant that German defeat was close. His impatience mounted along with Entente pressure, and Orlando pressed Diaz to plan an attack.
The plan of attack centered on the upper and middle Piave. Diaz would punch through the enemy lines around the road to Vittorio Veneto and Sacile, splitting Svetozar Boroević’s Sixth and Fifth armies, deployed respectively on the northern and southern halves of the Piave. This would make the Austrian positions on the Asiago plateau and Mount Grappa untenable.
The final blow for the Austrians came when the Italians, with Entente support, launched an attack all along the Trent and Piave fronts. Although the Austrians resisted in places, their line soon began to crumble, and the Italians and a British force both managed to establish bridgeheads across the Piave.
For a while there was still some fighting to be done. The Italians and their allies commenced a drive on the town of Vittorio Veneto in a successful attempt to separate the Austrian armies and cut the communications between them. The Austrian opposition crumbled apart as they commenced a withdrawal all along the line. The Trentino sector, that bastion of Austrian defense for the past three years, was overrun, and a general advance was commenced pushing north and east. As they fell back, over 300,000 Austrians became prisoners of war, mirroring the Italian disaster of Caporetto the year before.
The Italian campaign was over. The formal armistice began on 3 November 1918. In the end the Italians had helped bring the Austro-Hungarians to their knees, already weakened as they were by their titanic battles with the Russians on the Eastern Front. The Italians had played a major role by distracting the bulk of the Austrian Army that might otherwise have been redeployed to other fronts after the Russian Revolution.
The completeness of the Italian triumph can be seen in that the Austrians were forced to cede all the elements of the Italia Irredenta still under their control, including the South Tyrol, the Isonzo Valley, Trieste, Istria, Carniola and Dalmatia. The Italian gamble of 1915 may have paid off, but the cost had been excruciatingly high: some 651,000 killed during the three years of brutal war.