# Battles of the Isonzo

The Battles of the Isonzo (known as the Isonzo Front by historians, Slovene: soška fronta) were a series of twelve battles between the Austro-Hungarian and Italian armies in World War I mostly on the territory of present-day Slovenia, and the remainder in Italy along the Isonzo River on the eastern sector of the Italian Front between June 1915 and November 1917.

## Italian military plans

In April 1915, in the secret Treaty of London, Italy was promised by the Allies some of the territories of Austro-Hungarian Empire which were mainly inhabited by ethnic Slovenes, Croats and Austrian Germans.
Italian commander Luigi Cadorna, a staunch proponent of the frontal assault who claimed the Western Front proved the ineffectiveness of machine guns, initially planned breaking onto the Slovenian plateau, taking Ljubljana and threatening Vienna. The area between the northernmost part of the Adriatic Sea and the sources of the Isonzo River thus became the scene of twelve successive battles..
As a result, the Austro-Hungarians were forced to move some of their forces from the Eastern Front and a war in the mountains around the Isonzo River began.

## Geography

The 138 kilometres (86 mi) long Soča River at the time ran entirely inside Austria-Hungary in parallel to the border with Italy, from the Vršič pass in the Julian Alps to the Adriatic Sea, widening dramatically a 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 Postojna Gate to Inner Carniola and Ljubljana.
Italian troops did not reach the port of Trieste, the Italian General Luigi Cadorna's initial target, until after the Armistice.

## Primary sector for Italian operations

With the rest of the mountainous 640-kilometre (400 mi) length of the front being almost everywhere dominated by Austro-Hungarian forces, the Soča (Isonzo) was the only practical area for Italian military operations during the war. The Austro-Hungarians had fortified the mountains ahead of the Italians' 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 Soča (Isonzo) River. Cadorna had not 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 rainfalls during 1914–1918. Further, when attacking further north the Italian army was faced with something of a dilemma: in order to cross the Isonzo safely 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.

## Casualties

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 death total — some 300,000 of 600,000 — were suffered along the Soča River. 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).
More than 30,000 casualties were ethnic Slovenes, the majority of them being drafted into the Austro-Hungarian Army, while Slovene civilian inhabitants from the Gorizia and Gradisca region also suffered in many thousands because they were resettled in refugee camps where Slovene refugees were treated as state enemies in Italian refugee camps, where thousands died of malnutrition.

## Number of battles

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, Karfreit) in October 1917, which would otherwise form the Twelfth Battle of the Isonzo.
The fact that the battles were always named after the Isonzo River, even in Italy, was considered by some a propaganda success for Austria-Hungary: it highlighted the repeated Italian failure to breach this landmark frontier of the Empire.
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 1916
* 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
Brief summary of Isonzo battles :
| Battle | Dates | Italian casualties | Austro-Hungarian casualties | Outcome |
| First Battle of the Isonzo | 23 June – 7 July 1915 | 15,000 | 10,000 | Inconclusive |
| Second Battle of the Isonzo | 18 July – 3 August 1915 | 41,800 | 46,600 | Italian victory |
| Third Battle of the Isonzo | 18 October – 3 November 1915 | 66,998 | 41,847 | Austro-Hungarian victory |
| Fourth Battle of the Isonzo | 10 November – 2 December 1915 | 49,500 | 32,100 | Austro-Hungarian victory |
| Fifth Battle of the Isonzo | 9–15 March 1916 | 1,882 | 1,985 | Inconclusive |
| Sixth Battle of the Isonzo | 6–17 August 1916 | 51,000 | 42,000 | Italian victory |
| Seventh Battle of the Isonzo | 14–18 September 1916 | 17,000 | 15,000 | Italian victory |
| Eighth Battle of the Isonzo | 10 October 1916 – 12 October 1916 | 55,000 | 38,000 | Inconclusive |
| Ninth Battle of the Isonzo | 31 October – 4 November 1916 | 39,000 | 33,000 | Austro-Hungarian victory, Italian advance halted |
| Tenth Battle of the Isonzo | 10 May – 8 June 1917 | 150,000 | 75,000 | Limited Italian advance |
| Eleventh Battle of the Isonzo | 18 August – 12 September 1917 | 158,000 | 115,000 | Italian victory |
| Twelfth Battle of the Isonzo | 24 October – 19 November 1917 | 305,000 | 70,000 | Austro-Hungarian-German victory; end of the Isonzo Campaign |
| Total casualties | June 1915 – November 1917 | 950,180 | 520,532 | Central Powers victory, counteroffensives on the Piave river (First and Second battle) |

## In media

* Ernest Hemingway's A Farewell to Arms is partly during the events along this front.
* Italian poet Giuseppe Ungaretti's autobiographical poem, "I Fiumi", was written about the Isonzo whilst he was stationed on the front.
* Mark Helprin's A Soldier of the Great War refers to parts of the Isonzo campaign.
* The twelfth battle is the subject of the novel Caporetto by the Swedish author F. J. Nordstedt, Stockholm 1972.
* The Isonzo Front is the theme for the video game Isonzo by Blackmill Games.
* Fictional battle at Štanjel is featured in the video game Battlefield 1 as one of the playable maps.
* Emilio Lussu's A Soldier on the Southern Front is an account of the Isonzo campaign from the Italian side.