Battle of Caporetto (1917): Italy's Disaster on the Isonzo Front

The Battle of Caporetto, also called the Twelfth Battle of the Isonzo or the Battle of Kobarid, was an Austro-German offensive that broke the Italian front in the Julian Alps on 24 October 1917. Within days the Italian Second Army had collapsed and the whole army was retreating across the Venetian plain, losing hundreds of thousands of men as prisoners before it rallied on the Piave river in November.

Background: two years on the Isonzo

Italy entered the First World War against Austria-Hungary in May 1915. Its chief of staff, General Luigi Cadorna, launched eleven offensives along the Isonzo river between 1915 and 1917, described in the article on the Battles of the Isonzo. They gained Gorizia and part of the Bainsizza plateau but cost Italy enormous casualties.

The Eleventh Battle, in August and September 1917, left the Austro-Hungarian defenders badly strained. Vienna feared that one more Italian attack might break through towards Trieste and asked Germany for help. With Russia collapsing after the October Revolution and its own front quiet, Germany agreed to send troops.

The plan

A new Fourteenth Army was formed under the German General Otto von Below, with Konrad Krafft von Dellmensingen, a specialist in mountain warfare, as chief of staff. It included seven German divisions and several Austro-Hungarian ones. Further south, Austro-Hungarian forces under Svetozar Boroević were to attack along the lower Isonzo.

The main blow would fall in the narrow upper Isonzo valley between Flitsch (Bovec) and Tolmein (Tolmin), around the small town of Caporetto. This was a relatively quiet sector held by the Italian Second Army under General Luigi Capello. Many Italian troops were deployed well forward, with weak defences in depth, and their artillery was poorly coordinated with the infantry.

The breakthrough

The attack opened at 2 a.m. on 24 October 1917 with a short, intense bombardment, including gas shells. Near Flitsch, a German gas projector attack killed many Italian soldiers in their positions in a matter of minutes. At dawn, in fog and rain, the infantry moved forward.

The attackers used infiltration tactics. Small groups of storm troops bypassed strongpoints, moved along valley floors and pushed deep into the rear, leaving centres of resistance to follow-up units. By the evening of the first day German troops had reached Caporetto and opened a gap more than 20 km wide.

On 25 and 26 October a young German lieutenant, Erwin Rommel, led detachments of the Württemberg Mountain Battalion across the heights to capture Monte Matajur. His small force took several thousand prisoners, an exploit he later described in his book Infantry Attacks.

The retreat to the Piave

Cadorna ordered a general retreat to the Tagliamento river on 27 October. Roads became choked with troops, guns, civilians and refugees. Whole units surrendered or disintegrated, while others fought determined rearguard actions that allowed most of the army to escape.

The Tagliamento line could not be held, and the Italians withdrew again to the Piave river, which they reached around 9 November. The new front ran from the Adriatic along the Piave and up into the Monte Grappa massif. Austro-German attacks against it continued until about 19 November and then into December, but the line held.

Cadorna was dismissed on 8 November and replaced by General Armando Diaz, who rebuilt morale by improving food, leave and conditions. At a conference at Rapallo in early November, Allied leaders agreed to create the Supreme War Council and sent eleven British and French divisions to Italy.

Why the Italian army broke

Historians identify several causes of the collapse. The most immediate was tactical: the Second Army was deployed too far forward, with few reserves behind it, and its commander Capello had prepared for an offensive rather than a defence. When German units pushed up the valleys, the Italian positions on the heights were cut off from behind.

Communication also failed. Telephone lines were cut by the bombardment, and senior commanders received confused and late reports. Some Italian artillery, under orders not to fire without permission, stayed silent at the critical moment.

Morale was a deeper problem. Italian soldiers had endured eleven bloody offensives, harsh discipline that included the execution of soldiers chosen by lot after unit failures, poor food and little leave. Cadorna later blamed cowardice, but the parliamentary inquiry and most historians placed the main responsibility on the high command. Many units fought bravely in rearguard actions during the retreat.

The wider strategic picture also mattered. With Russia out of the fighting after the revolutions of 1917, Germany could spare experienced divisions and artillery for Italy, while Italy’s allies had committed their reserves to Flanders and could send help only after the disaster had happened.

By the numbers

Large numbers of Italian soldiers were also separated from their units during the retreat, and hundreds of thousands of civilians fled the occupied provinces of Friuli and Veneto.

Key people

• Luigi Cadorna (1850–1928): Italian chief of staff, who blamed the defeat on cowardice among his troops in a notorious communiqué and was removed soon after.
• Otto von Below (1857–1944): German general commanding the Fourteenth Army.
• Konrad Krafft von Dellmensingen (1862–1953): chief of staff and planner of the offensive.
• Armando Diaz (1861–1928): Cadorna’s successor, who stabilised the front and later led Italy to victory.
• Erwin Rommel (1891–1944): German junior officer, later a famous Second World War field marshal.

Consequences and legacy

Caporetto was the worst defeat in Italian military history. Yet it did not knock Italy out of the war. The Piave line held, the June 1918 Austro-Hungarian offensive on the Piave failed, and in October–November 1918 Italy won the Battle of Vittorio Veneto, which led to Austria-Hungary’s armistice.

The defeat prompted a parliamentary commission of inquiry, which in 1919 criticised Cadorna, Capello and other senior officers rather than the ordinary soldiers. The word “Caporetto” entered Italian as a byword for any crushing failure.

The battle also had a cultural afterlife. Ernest Hemingway, who served as a Red Cross ambulance driver in Italy in 1918, set the retreat at the centre of his novel A Farewell to Arms (1929). Today the Kobarid Museum in Slovenia tells the story of the Soča front, and an Italian ossuary built in 1938 on a hill above the town holds the remains of more than 7,000 Italian soldiers. Walking trails link surviving trenches, caverns and cemeteries along the former front line.

Timeline

• 1917, August–September: The Eleventh Battle of the Isonzo strains the Austro-Hungarian defences.
• 1917, 24 October: The Austro-German offensive breaks through near Caporetto.
• 1917, 25–26 October: Rommel’s detachment captures Monte Matajur.
• 1917, 27 October: Cadorna orders a general retreat to the Tagliamento.
• 1917, 7 November: The Rapallo conference creates the Allied Supreme War Council.
• 1917, 8 November: Cadorna is replaced by Armando Diaz.
• 1917, around 9 November: The Italian army reaches the Piave line.
• 1918, 24 October–4 November: Italy wins the Battle of Vittorio Veneto.

Why it matters

Caporetto showed how surprise and infiltration tactics could shatter a static front, foreshadowing the German offensives of 1918. For Italy it was a national trauma, but the recovery that followed on the Piave became an equally powerful part of its memory of the war.