Start of the eleventh battle of the Isonzo

On 17 August 1917, on many sectors of the front on the Isonzo, the Italian batteries were firing ranging fire so dense that, as General Luigi Cadorna later wrote, it differed little from a barrage. For several days the Austrians had had no doubt about what was coming. The Italian official history counts the Eleventh Battle of the Isonzo from this day; it was the largest offensive the Italian army carried out in this war. The full bombardment from Tolmin to the Adriatic began at dawn on 18 August, and the infantry attacked on the morning of 19 August. Cadorna threw 51 divisions into the battle, three quarters of his infantry, and, according to the Austrian official history, about 5,200 guns and trench mortars. According to the same source, the Austro-Hungarian Isonzo Army had about 1,900 guns and 300 mortars during the battle.

The second attempt this year

Barely two and a half months had passed since the end of the Tenth Battle at the beginning of June. The May offensive had given the Italians the Kuk and Vodice ridge above Plava, but had cost them about 160,000 men, and the Austro-Hungarian counter-attack had taken back most of their gains on the Karst plateau. In June the Italians also attacked in the Trentino, in the Battle of Mount Ortigara, but the Austrians rightly believed that Cadorna’s main objective remained the Isonzo and the road to Trieste.

Cadorna again counted on his allies. In July he asked the French and British for at least a hundred heavy guns and wrote to General Ferdinand Foch that because of the shortage of ammunition he would not attack before the end of August. At the Paris conference at the end of July he demanded ten divisions and 400 guns for a joint, decisive offensive against Austria-Hungary. The British and French promised help, but only for the spring of 1918. For the time being the Italians had to attack on their own. Over the summer they raised six new divisions and many batteries of heavy artillery, and according to Treccani they concentrated more than 600 of their army’s 887 battalions on the Julian front.

Cadorna’s and Capello’s plan

This time Cadorna wanted to strike simultaneously along the whole front from around Tolmin to the sea, so that the defenders, outnumbered two to one, could not shift reserves from one sector to another. He issued no detailed written orders, only general directives. The 3rd Army of the Duke of Aosta, Emanuele Filiberto, was again to attack on the Karst, towards Komen and Hermada. The main role, however, went to the 2nd Army of General Luigi Capello, the conqueror of Gorizia in the Sixth Battle. It was to cross the Isonzo above Plava and take the Bainsizza plateau (in Slovene Banjška planota), stony, waterless and almost roadless ground between the Isonzo, the Čepovan valley and Monte Santo, and then come out onto the Trnovo plateau in the rear of the Austrian defences at Gorizia.

Capello went further. He made his “main objective” the Austrian bridgehead at Tolmin, which he wanted to take by wheeling north from the plateau. The attack was to be carried by the XXVII, XXIV and II Corps, “with strength increasing from south to north”. The crossing of the Isonzo, cut deep into the rock, was the hardest part of the plan. On a stretch of about 12 kilometres between Anhovo and Doblar the engineers prepared material for fourteen bridges and footbridges, built new roads down from the Kolovrat ridge to the river and brought in carts on rubber wheels to carry it there quietly. The commander of the XXIV Corps, General Enrico Caviglia, studied the Austrian fortifications for more than a week, helped by a Czech deserter from the positions at Kanal who claimed to be a captain.

The Austrians wait

At the beginning of July General Svetozar Boroević’s Isonzo Army had only one division more than before the May battle. The Russian offensive in Galicia made it impossible to bring troops from the east, so the South-Western Front command brought in individual battalions and batteries from the Tyrol and Carinthia. Boroević expected the main blow on the Karst and on the road to Trieste. On the Bainsizza plateau, which until May had been regarded as quiet, the defensive line was weak and still being built under the eyes of the Italians, who could see every movement from the Kuk ridge and Hill 652. On the Isonzo itself, north of Kanal, six kilometres of the bank were guarded by only two Hungarian Landsturm battalions, and further south by the overstretched 21st Rifle Division.

The Italian assault had been expected as early as the end of July. When it did not come, on 7 August Archduke Eugen, commander of the South-Western Front, concluded that the battle was near and ordered further battalions from the Tyrol to be kept ready. From 14 August the Italian artillery grew sharply in strength. Long-range batteries, directed by airmen, shelled the reserves’ billets, the approach roads and the headquarters. At Tolmin a large ammunition dump blew up, and the headquarters of the XV and XXIV Corps had to move further to the rear. In the middle of August the number of Italian deserters grew from day to day. Whole groups crossed over to the other side shouting “To Mauthausen!”, because there was a camp for Italian prisoners at Mauthausen. The Austrians took this as a sign that morale in part of the Italian army had weakened. The statements of prisoners and the behaviour of the Italian artillery made it almost certain that the assault would begin on 18 August.

In those days, at the far northern end of the front, an episode took place that the Austrian official history describes with admiration. The garrison of the summit of Krn had suspected for weeks that the Italians were driving a gallery beneath it. Reserve Lieutenant of Engineers Gjuro Hoffmann and thirty men began cutting a tunnel through the rock towards it, and in the middle of August came upon an Italian mine already ready for firing. He defused it just before it was due to go off and drove off the astonished Italian miners. According to the Austrians, the Italians then gave up the assault on Krn that was to have opened the battle. Hoffmann was awarded the Knight’s Cross of the Military Order of Maria Theresa for this.

The bombardment

At dawn on 18 August several thousand guns opened up on the Isonzo, from Krn to the sea. According to Cadorna, under the fire the parapets of the Austrian trenches collapsed, the wire entanglements vanished, and the defenders took shelter ever deeper in caverns. On the evening of 18 August Tolmin, the villages on the plateau and the woods on the Trnovo and on the slopes of Hermada were burning. On the night of 18–19 August the engineers of the 2nd Army began building bridges across the Isonzo, and before dawn the first Bersaglieri were already on the other bank. Only about half of the planned crossings could be built, however, and on the morning of 19 August the infantry went in to the assault from Tolmin to the Adriatic. A month of the heaviest fighting on the Italian front had begun, which brought the Italians the Bainsizza plateau and Monte Santo, but not the breakthrough they had hoped for.