100 Years Ago: Italy Loses an Entire Army at Caporetto

The Battle of Caporetto began 100 years ago tomorrow at 2:00 a.m. on 24 October 1917 with an artillery bombardment. Italian trenches were destroyed by the Austro-German Army's brief, but very intense, artillery barrage, and the survivors of the artillery attack were quickly surrounded and overrun by the fast-moving enemy columns. The Austro-German infantry assault was greatly helped by the dense fog that provided them with cover until they were almost on top of the Italian trenches. Poison gas was used widely and proved especially lethal in the Plezzo basin, where possibly the most successful chemical warfare attack in history took place. The XIV Austro-German Army took only two days to capture all their immediate objectives around the Isonzo River. The subsequent exploitation, pushing the Italian forces back to the Piave River, lasted about a month. The key to the success of the Central Powers at Caporetto was a double breakthrough that shattered the entire Italian defensive deployment the first morning of the battle. 

Initial Attack & Advance by Central Powers at Caporetto

Tolmino: Southern Breakthrough Point

Because of the bridgehead at Tolmino (see map), German forces deployed there could attack on both sides of the Isonzo River. Further, a successful breakthrough at this point would place them behind the first and second Italian lines on the right (east) side of the river. This decisive attack was launched from the Tolmino bridgehead against the Italian XXVII Corps. Italian defenses were far stronger at Tolmino than at Plezzo, but still inadequate. Few of the XXVII Corps's artillery batteries managed to open fire before being overrun. Italian command and control were successfully targeted by Austro-German artillery and Italian Second Army's headquarters was left unable to effectively issue orders or receive news from the front. Throughout the battle, the Italian artillery performed miserably, either because the batteries were overrun or because they never received orders to open fire. The Italian infantry was left with little or no artillery support throughout the battle. Tens of thousands of Italian troops deployed on the mountains on the east side of the Isonzo were captured en masse, many never firing their weapons. 

Italian Soldiers with German Captors Near Caporetto, October 1917

Plezzo: The Northern Breakthrough Point

The assault through the Plezzo basin was preceded by a massive gas attack on the night of 23-24 October. Italian gas masks were ineffective against the mix of phosgene and diphenylchlorasine used by the Germans. The entire Italian 87th regiment deployed in defense of the Plezzo basin was killed in the attack. At dawn, the I Austro-Hungarian Corps attacked down the Isonzo valley from Plezzo, encountering only sporadic and poorly coordinated resistance until they reached the Saga Narrows.

Near Knock-Out

At Caporetto, the Italian Army suffered one of the most stunning defeats of the entire First World War. Italian casualties totaled 40,000 dead and wounded, over 280,000 prisoners and 3,150 artillery pieces captured. The Italian Army was reduced in size by one half, from 65 infantry divisions to 33 and the Italian province of Friuli was abandoned to the enemy along with much of the Veneto Province. The entire Italian Second Army was wiped off the board. Today, 100 years after the event, Italians still say "It was a Caporetto" to mean "It was a complete disaster."