“April is coming to an end. The enemy battalions [...] deployed opposite the First Army are over two hundred; guns, including many large- and medium-caliber, more than a thousand. A huge avalanche”
(Cap. Cesare Pettorelli Lalatta)
Austria-Hungary started its first major offensive against the Trentino section of the Italian front between 15th May and 26th June 1916. No precedents existed for such a large operation in an Alpine environment. About 380,000 soldiers of the Austro-Hungarian army, supported by 1000/1500 artillery pieces (including some 420 mm howitzers), had managed to surprise the unsuspecting Italian troops, who, at the date of the attack, were still deployed in offensive positions. It was less than a year after Italy had entered the war alongside the Entente Powers.
Although the change of front had not surprised the Danubian Monarchy, the opening of hostilities by the Italians against the Austro-Hungarian Empire felt like a stab in the back. Over Christmas 1915, the Central Powers had reorganized their forces on the offensive, exploiting the victories won on the Eastern and Balkan fronts. Conrad von Hötzendorf, Austro-Hungarian Chief of General Staff, believed that Italy was the only enemy which could be crushed with decisive action. In fact, the Italian front was extremely unbalanced, shaped like a big “S”, lying horizontally with the Trentino salient wedged behind the bulk of the Royal Italian Army deployed along the Isonzo river and on the Carso plateau.
The Austro-Hungarian plan for attacking Italy had concentrated on the Trentino area since 1908, but the Empire, militarily engaged on almost all its borders, did not have enough troops to carry out the operation. On several occasions Von Hötzendorf asked the head of the German Chief of General Staff General von Falkenhayn for support in carrying out the offensive in “South Tyrol”. The reasons behind the sharp refusal by the Germans were precise: the Italian front was not decisive for the conflict and ousting Italy would not have achieved a final victory. Moreover, in the meantime, the Germans were planning the parallel offensive of Verdun, which, in their view, would devastate France. Curiously, on the Italian side, Cadorna never believed in a possible offensive in the Trentino area for reasons similar to those explained by von Falkenhayn.
Von Hötzendorf decided to go it alone by taking troops from Galicia and the Isonzo area. Preparations began in February with the deadline planned for 11th April 1916. The Tyrolean rail network was, however, unable to withstand such a large movement of men and materials. Another negative factor was the inclement weather blocking railways with heavy snowfall and rain. On 15th May, about a month later than planned, everything was ready. Meanwhile, rumours that a major attack was imminent had leaked through both from Austro-Hungarian deserters and the Italian intelligence service. It was at this point that the word Strafexpedition (Punitive Expedition), never used in an official context, appeared. Evidently the name circulated unofficially among the Austrian troops while in Italy the term became famous only after the end of the conflict.
Cadorna, whilst not believing the rumours, had, however, planned to move the line back into a defensive position. During an inspection conducted on 26th April he discovered that his orders had been circumvented by General Brusati. The latter, commander of the First Army, had tried, and failed, to occupy the peaks and other areas useful for containing a possible Austrian attack without losing ground. Cadorna, just six days before the offensive, relieved Brusati of the command. On 15th May, the Austro-Hungarian troops overwhelmed the Italians. Supported by a solid line of forts, the Austro-Hungarian army devastated the Italian positions with artillery, and then occupied them with the infantry. Key strategic positions such as the plateau of Tonezza and Bocchetta Portule were quickly captured: the latter vital for the control of the Asiago Plateau.
Already by the end of May Mount Cimone had been lost along with the towns of Asiago and Arsiero: the attack culminated on 3rd June with the Austro-Hungarian capture of Mount Cengio, strenuously defended by the Grenadiers of Sardinia. Even though fighting did not diminish in intensity, the parallel Brusilov offensive in Russia forced Conrad von Hötzendorf to switch troops and artillery back to Galicia. It was Cadorna who had pressured the Russian allies, asking for help, and deploying additional troops from the Isonzo. The obstinate Italian resistance, despite the inferior artillery, still managed to stifle the enemy offensive just before the Vicenza plain. On 28th May, in one of his letters, Cadorna himself had written “I am organizing transport [...] destined to save the situation. Provided that the Austrians do not send extra forces [...] because in that case I would be obliged to take more serious decisions.” The Italian soldiers could not believe their eyes when they discovered that the Austro-Hungarian forces were retreating and the immediate counter-offensive that followed managed to regain some of the ground lost. The attack so strongly desired by Hötzendorf had been contained and repulsed just before reaching the plain.
Although the Italian front was considered secondary, the failure of the Strafexpedition brought about consequences of primary importance: Brusilov, thanks to the removal and redeployment in Italy of Austro-Hungarian troops from the eastern front, won a decisive victory that rocked the very foundations of the Austro-Hungarian Army. Germany, considering the serious conditions of its ally, was forced to help by removing troops from the Western Front to fill the gaps opened up on the Eastern front. In Italy the consequences were mainly political, with the resignation of Salandra. Nevertheless, the structural weaknesses of the Italian army remained intact. In many ways, the resistance to the bitter end offered by the Italian troops had failed to settle the internal problems of the Royal Italian Army. These crucial matters would re-emerge tragically fifteen months later at Caporetto.