John Foot writes:
Allied to Germany and Austria-Hungary through the Triple Alliance of 1882, Italy initially remained neutral in the First World War, on the grounds that the alliance was a defensive arrangement. Then, on 24 May 1915, it declared war on Austria-Hungary. The decision was taken by the king and a minority of the cabinet, without the approval of parliament, after secret meetings in London at which the Entente powers promised that, in the event of victory, Italy would be able to annex the regions of Austria-Hungary largely populated by Italians. Most Italians were opposed to joining the war, although an organised and violent minority had campaigned vigorously in favour. Five million Italians were called up, and the conflict caused serious strain in a country which had only recently been unified and whose population identified far more with their local village or region than with the nation. Most of the fighting took place around the Isonzo River in the north-east, but the front stretched west through Trentino and Alto Adige, and it was here that what Mark Thompson describes as ‘the white war’ really took place.