Battles of the Isonzo


July 3, 2022

The battles of the Isonzo refer to twelve bloody clashes between Italy and Austria-Hungary, which took place from June 23, 1915 to September 12, 1917 during the First World War. This name is that of the Isonzo river (called Soča in Slovenian) because the front was located near its valley. This area is now largely in Slovenia. These battles were part of the "mountain war" and were deadly, 300,000 Italians losing their lives (500,000 wounded), as well as 200,000 Austro-Hungarian soldiers (400,000 wounded).

Aim of the battles

The purpose of these engagements was for Italian forces to seize the Austro-Hungarian port of Trieste, two-thirds of whose inhabitants were Italian. The Italian troops faced many physical obstacles, including the Isonzo (Soča), a river that meanders along the border, overlooked by steep mountains. The Austrians could count on a better quality of their armaments, in particular on more powerful artillery pieces, but they were in numerical inferiority compared to the Italians. However, mountain warfare gives defenders a big advantage over attackers, even if the former are outnumbered. At the same time, Austria-Hungary had to cover two other fronts: the Russian front and the Serbian front. This explains the imbalance of forces and the passive attitude of the Austro-Hungarian army which, until 1917, suffered Italian initiatives on the Isonzo without being able to carry out large-scale attacks.

Successive battles

On May 23, 1915 Italy, hitherto neutral, declared war on Austria. Even before the first Battle of the Isonzo, the entire Imperial and Royal Navy, based in Pula, went out to sea to bombard the eastern coast of Italy between Venice and Barletta. She succeeded in surprising the Italian fleet near Venice, so that the latter was able to put up little resistance and the Imperial and Royal Navy were able to complete their attack without suffering any losses.

First Battle of the Isonzo (June 23 – July 7, 1915)

On June 23, 1915 the Italians began the first battle of the Isonzo with an intense pounding, for 7 days, of the Austro-Hungarian front and artillery pieces. Due to the lack of experience of the Italian gunners, however, they did little damage. Forces present: Italy: 225 battalions and 111 squadrons as well as 700 artillery pieces. Austria-Hungary: 84 battalions, 13 squadrons and 354 artillery pieces. This corresponds to a ratio of forces of 3 against 1. The Italian 3rd Army aimed to break the front between Monfalcone and Sagrado, towards the high plateau of Doberdò, while the 2nd Army advanced between Monte Sabotino and Podgora. The aim being to conquer the bridgehead of Görz (in Italian Gorizia, in Slovenian Gorica), to cross the Isonzo, to seize the mountains Kuk and Priznica (Kote 383) and also to carry out an attack against the head of Tolmin Bridge (in Italian Tolmino, in Slovenian Tolmin). Despite its triple superiority, the Italian army could not achieve any of its aims. Only in Sagrado does it manage to push on to the high plateau of Doberdò. Losses: Italy: 15,000 men (including 2,000 dead), Austria-Hungary: about 10,000 men.

Second Battle of the Isonzo (July 17 – August 3, 1915)

Forces present: Italy: 260 battalions and 840 artillery pieces (a total of 290,000 Italian soldiers were used during the offensive), Austria-Hungary: 105 battalions and 420 artillery pieces, with a reinforcement of 25 battalions until the end of the battle. This time again the offensive began with a shelling, which however lasted only 2 days. The Italian 3rd Army was to break through in dir