Although during WWI Italy did not declare war on Austria-Hungary until 23rd May 1915, by the end of the war in 1918, almost 700,000 Italians were dead, 950,000 were wounded and 250,000 were crippled for life.
Italy was rather unprepared for this massive venture. After the declaration of war the army was nowhere near being on the appropriate footing, and money for armaments was scarce. Nevertheless, the Italian armies marched into Austrian territory in the northeast of Italy, with some success against armed forces who had their hands full elsewhere. However, a prolonged stalemate quickly developed which was not broken until the end of 1917. Then the Austrians and Germans, freed from the burden of the Russian front, attacked, inflicting a humiliating defeat on the Italians at the Battle of Caporetto.

The Austro-German armies moved south to threaten the peninsula; Italy seemed to be in grave danger, and British and French troops were sent to the rescue. The Italians, however, responded to the challenge with great fortitude and spirit. Before the arrival of the Allied forces, the greatly outnumbered Italian army halted the Austro-German advance on the River Piave - a military feat which has gone down in nationalist folklore, and which was celebrated in the patriotic song 'Il Piave mormorò ... non passa lo straniero' (The Piave whispered ... the foreigner shall not pass). By the autumn of 1918 the Italian and Allied forces were driving the Austrians back towards the north.
My great-uncle, Mario, was only seventeen when he joined the Italian army in 1915. He was a young boy full of ideals and captured by the words and speeches of the nationalist poet Gabriele D'Annunzio who encouraged his countrymen to free the Italian territories under the Austrian oppression. He fought in the first Battle of Caporetto and then was sent further to fight in the trenches on the Italian-Austrian border. His trench was near Monte Grappa, in Veneto:

Life in the trenches was rough on soldiers. They had to worry about rats, catching diseases, shellfire, and body lice. Food was also in short supply towards the end of the war. If you were injured, it could take a while until you were treated. Some injuries were so bad that they had to be amputated. Mario was not injured by an enemy bullet or a shell. On the 23rd October 1918 he suffered a bad attack of appendicitis. No doctor and no transport to a field hospital were available so in the morning of the 24th he died of peritonitis after hours of agonizing pains. He was buried in a field nearby. Few hours later his fellow soldiers launched a final attach on the Austrian enemy lines and broke through. On the 4th November 1918 an armistice was signed between Italy and Austria. The war was over.
My great-uncle did not die as a war hero. He was not awarded any medal. My great-grandmother just received a short letter that informed that her son was dead. She never saw his body.
It is now possible to visit the “ruins” of the trench where my great-uncle Mario died. My granddad never wanted to visit it. Neither did my dad. Nor will I.

Vigil
Cima Quattro, December 23, 1915
An entire night
thrown down
beside a butchered
companion with his
grimacing
mouth
turned
to the full moon
with his congested hands
thrust
into my silence
I wrote
letters full of love
I have never held
so hard to life
(Giuseppe Ungaretti, Italian Poet, 1888-1970 – in translation)