This offensive action, it now appeared, had really begun on May 12, 1917, when, in the morning, fire was opened along the whole line from Tolmino to the sea. It was maintained with a regularly quickened rhythm until the morning of May 14, 1917, when it was intensified to a powerful drum fire. During the first part of the bombardment the Austrians reacted but feebly. It seemed as though the Austrians had been taken by surprise, but their reply was more vigorous on May 13, 1917, and extremely violent on the morning of the 14th. Austrian batteries then opened a heavy curtain of fire, pouring thousands of projectiles on the trenches in the Italian line.
Undeterred by this tempest of fire, the Italian infantry, toward noon, leaped over the parapets and dashed forward toward the objectives previously assigned. These positions were almost all difficult ones, and some of them hitherto had been regarded as impregnable; such, for instance, as the heights on the left bank of the Isonzo, from Plava to Salcano Pass. The steep slopes, covered with rocks and dotted here and there with thick clumps of brush, constituted a formidable obstacle to an infantry advance. Successive lines of trenches, prepared months before above deep caverns, well supplied with defensive and offensive material, were defended by seasoned troops and protected by batteries placed so as to flank attacks with their fire. Notwithstanding these conditions, the Italian infantry advanced.
This vigorous offensive movement was continued by the Italian troops on May 15, 1917. Ably supported by artillery, they succeeded in establishing themselves on the steep and wooded heights along the eastern bank of the Isonzo, north of Goritz, which had been transformed by the Austrians into a formidably fortified defensive position. On the left wing one of the Italian columns, after forcing a passage across the river between Loga and Bombrez, captured the last-named village and fortified itself there.
In the center the heights of Hill 383, northeast of Plava, were captured, while the Florence infantry brigade and the Vaellino brigade, after taking by assault the villages of Zagora and Zagomila, which were infested by machine guns, carried the crests of Monte Cucco and Monte Vodice with great dash.
On the right wing the other Italian columns made considerable progress on the steep slopes of Monte Santo. Fierce Austrian counterattacks, prepared and supported by a bombardment of exceptional violence, were all repulsed.
In the area east of Goritz the Messina brigade conquered Hill 174 north of Tivoli, which was strongly fortified and stubbornly held by the Austrians, whose insistent counterattacks were beaten back.
The city of Goritz suffered a heavy bombardment from Austrian batteries, and some buildings were seriously damaged.
On the remainder of the front down to the sea there were lively artillery actions. The Austrian rear lines were again effectively bombed by air squadrons and during the night by airships.
In the first two days of their advance the Italians made 3,375 prisoners, among them ninety-eight officers. They also captured a mountain battery, about thirty machine guns, and much war material, including arms and ammunition.
On the following day, May 16, 1917, the Austrian resistance stiffened somewhat. In spite of this the Italian advance continued. Fighting in the zone between Monte Cucco and Vodice was bitter and lengthy. Considerable Austrian masses, supported by the fire of numerous batteries, were repeatedly launched against Italy's new positions. Each time they were repulsed, and the Fochux bastion of Monte Cucco from Height 611 to Height 525 remained firmly in Italian hands. Moreover, the Italians made appreciable progress toward the important summit of Height 652, on the Vodice.