Battles of the Isonzo

For the Ostrogoth invasion of Italy, see Battle of Isonzo (489).

The plain at the confluence of the Isonzo and Vipava river around Gorizia: the main passage from Northern Italy to Central Europe.

"Battles of the Isonzo" were a series of 12 battles between the Austria-Hungarian and Italian armies in World War I. They were fought along the Isonzo River on the eastern sector of the Italian Front between June 1915 and November 1917. Most of the battles were fought on the territory of modern Slovenia, and the remainder in Italy.

During the First World War, the Isonzo valley was part of the Alpine sector of the Italian Front, along which the armies of Italy and Austria-Hungary clashed. It is known as the Soška fronta in Slovene and is usually translated as the Isonzo Front by historians.

Geographical location and strategic importance

Remains of an Austro-Hungarian fortification between Bovec and Log pod Mangrtom.

The Soča is located in present-day Slovenia and Italy. During World War I, however, the sixty-mile long river ran entirely inside Austria-Hungary in parallel to the border with Italy. The valley is flanked by relatively high mountains on both sides, which are lower in the western and higher on the eastern side. It runs from the Vršič and Predil Pass in the Julian Alps to the Adriatic Sea, widening dramatically just few kilometers north of Gorizia, thus opening a narrow corridor between Northern Italy and Central Europe, which goes through the Vipava Valley and the relatively low north-eastern edge of the Kras plateau to Inner Carniola and Ljubljana. The corridor is also known as the "Ljubljana Gate".

The Italian army wanted to break through this passage in order to penetrate in central Carniola and then into Styria to the heart of Austria. The area between the northernmost part of the Adriatic Sea and the sources of the river Soča thus became the scene of twelve successive battles.

Primary sector for Italian operations

Italian troops entrenched along the river Soča/Isonzo.

With the rest of the mountainous 400-mile length of the Front being almost everywhere dominated by Austro-Hungarian forces, The Isonzo was the only practical area for Italian military operations during the war. The Austrians had fortified the mountains ahead of the Italians' long-expected entry into the war on 23 May 1915.

Italian Chief of Staff Luigi Cadorna judged that Italian gains (from Gorizia to Trieste) were most feasible at the coastal plain east of the lower end of the Isonzo. However he also believed that the Italian army could strike further north and bypass the mountains either side of the river so as to come at the Austro-Hungarian forces in the rear.

Not that he expected operations in the Isonzo sector to be easy. He was well aware that the river was prone to flooding - and indeed there were record rain-falls during 1914-18.

Further, when attacking further north the Italian army was faced with something of a dilemma: in order to safely cross the Isonzo it needed to neutralise the Austro-Hungarian defenders on the mountains above; yet to neutralise these forces the Italian forces needed first to cross the river - an obstacle that the Italians never succeeded in satisfying.

In the south (along the coastal zone) geographic peculiarities, including an array of ridges and valleys, also gave an advantage to the Austro-Hungarian defenders.

Huge casualties

File:KostnicaKobarid.jpg

Monument to fallen Italian soldiers above Kobarid.

Despite the huge effort and resources poured into the continuing Isonzo struggle the results were invariably disappointing and without real tactical merit, particularly given the geographical difficulties that were inherent in the campaign.

Cumulative casualties of the numerous battles of the Isonzo were enormous. Half of the entire Italian war casualty total - some 300,000 of 600,000 - were suffered along the Isonzo. Austro-Hungarian losses, while by no means as numerous were nevertheless high at around 200,000 (of an overall total of around 1.2 million casualties).

Number of battles

Austro-Hungarian supply line over the Vršič pass.

With almost continuous combat in the area, the precise number of battles forming the Isonzo campaign is debatable. Some historians have assigned distinct names to a couple of the Isonzo struggles, most notably at Kobarid (Caporetto) in October 1917, which would otherwise form the Twelfth Battle of the Isonzo.

The Isonzo campaign comprised the following battles:

• First Battle of the Isonzo - 23 June–7 July 1915
• Second Battle of the Isonzo - 18 July–3 August 1915
• Third Battle of the Isonzo - 18 October–3 November 1915
• Fourth Battle of the Isonzo - 10 November–2 December 1915
• Fifth Battle of the Isonzo - 9–17 March 2000007
• Sixth Battle of the Isonzo - 6–17 August 1916
• Seventh Battle of the Isonzo - 14–17 September 1916
• Eighth Battle of the Isonzo - 10–12 October 1916
• Ninth Battle of the Isonzo - 1–4 November 1916
• Tenth Battle of the Isonzo - 12 May–8 June 1917
• Eleventh Battle of the Isonzo - 19 August–12 September 1917
• Twelfth Battle of the Isonzo - 24 October–7 November 1917 also known as the Battle of Caporetto

References in literature

• The twelfth battle is the subject of the novel "Caporetto" by the Swedish author F.J. Nordstedt (eg. Christian Braw), Stockholm 1972.
• Ernest Hemingway's A Farewell to Arms is partly set in the events along this front.

External links

• FirstWorldWar.Com The Battles of the Isonzo, 1915-17
• FirstWorldWar.Com Battlefield Maps: Italian Front
• 11 battles at the Isonzo
• The Walks of Peace in the Soča Region Foundation. The Foundation preserves, restores and presents the historical and cultural heritage of the First World War in the area of the Isonzo Front for the study, tourist and educational purposes.
• The Kobarid Museum (in English)
• Društvo Soška Fronta (in Slovene)
• Pro Hereditate - extensive site (in English, Italian, and Slovene)