While the world hears little about strategic plans that fail to work out, it is believed that the Austrians in May, 1915, had in mind to let the enemy obtain a good start in his advance against Trieste. Then, when the Italian operations were well under way, and the two railroads from Venice were choked with their supplies, the Austrians probably intended to launch a swift attack upon Verona and the rich cities of Lombardy, thus cutting off the chief centers of Italian industry. At the same time, they undoubtedly meant to send an invading army through the passes of the Carnic and Julian Alps from their base at Tarvis, and by a sudden swoop southward take the Italian forces on the Isonzo in the flank. At least this is what the Italian staff believed was their plan, and they arranged their own forces accordingly.
This was the reason for the extensive Italian drive during the third week of May, 1915, at all the mountain passes of the long frontier. For almost any of these passes might prove to be the gateway of invasion, whereas, once captured, they could be held by a few battalions. But behind each force that occupied the passes won in the first Italian dash was a large reserve ready to lend support wherever the enemy tried to break through. The Italians were not kept long in suspense as to where this thrust from the north first would come.
On May 29, 1915, under cover of a heavy fog, the Austrians concentrated a strong force from Villach, brought them to Mauthen, and from that point launched five successive attacks in an effort to win back the pass of Monte Croce in the Carnic Alps. The Alpini met the attacks with musketry and machine-gun fire, then, after the last attempt had failed, leaped from their trenches and drove the Austrians down the valley.
Thus began the battle of Monte Croce, an engagement described in the official bulletins of both countries in a way that gave the world its first intimation of the peculiar features of this mountain warfare. Each side had large reserves, and the struggle for the pass continued day and night, the Italians pushing over the neighboring passes and gathering their strength for a counterattack when the Austrians were exhausted.
On June 8, 1915, the Italians stormed Freikofel, a height commanding the Plocken Plateau, and took the Pass of Valentina and the Pass of Oregione, 7,500 feet high, and overlooking the wooded valley of Gail. The Alpini won Oregione by climbing through ice and snow over Paralba Mountain and fighting their way downward. Undaunted, General Dankl called up a fresh corps.
On the night of June 14, 1915, the Austrians made a supreme effort to break through the Italian line and put into effect his plan of pouring an army through the Carnic Alps to attack the flank of the main Italian army. Although 100,000 men were engaged in this battle, the ground permitted no massed movements. For miles the saddle of Oregione, the snow-clad sides of Paralba, and every smaller peak and ravine extending to Monte Croce and Freikofel were speckled with fighting men. After the two sides came to grips, the big guns held their fire, and it was man to man and bayonet against bayonet. At one point only did the Austrian thrust reach Italian soil. For a short time the Austrians were on Paralba at an elevation of 8,840 feet, but threatened both in the flank and in the rear they were forced to retreat and take refuge in their prepared positions on Steinwand, a huge limestone mountain overlooking the Gail Valley.
The strategic idea of General Cadorna is more easily understood when one studies the railway map of the Austrian territory north of the Carnic border. Here their railway line through the Drave Valley passed closer to the boundary line than did the Italian system on the south, and they could bring up fresh troops with more speed. In the Gail Valley they had a wide region in which they could mass hidden from the enemy, and they had a good road up the mountains from Mauthen, while the Italians had to depend upon rough tracks through the valley. Although Cadorna had the hard task of keeping the doorway to Venice closed while he attacked the enemy on both flanks, he accomplished his purpose.
The Italian army operating in the province of Cadore won its next success in an attack upon the village of Cortina, situated in a salient of the frontier, 4,000 feet high, amid some of the most beautiful scenery in the world. Cortina was taken on May 30. The Austrians had barricaded the famous road winding up through the Dolomites, and dug elaborate trenches; but the Italians, by superhuman efforts, moved up their mountain guns, while the Alpini scrambled over the mountains by the glaciers of Serapis and the tarns of Croda da Lago, and descended into Cortina on either side. Then, holding the enemy on the east, they advanced into the Tyrol westward to Falzarego.
In this region they had an experience which illustrated the foresight of the Austrians in preparing for the attack they believed would come. Some years before an Austrian had built a hotel in a deep ravine shut in by walls of limestone and very difficult of approach. Tourists had commented upon the lack of practicability of the man who placed a hostelry in so inaccessible a spot. But when the war came it developed that the hotel builder probably had a subsidy from the Government. For sandbags, machine guns, and quick-firers quickly converted the hotel into an excellent fort, which dominated the famous ravine. Thanks to the hardiness and ingenuity of their picked Alpine troops, the Italians, after a week of hard fighting, cleared the mountains above the ravine and dropped upon the hotel fort.
By June 9, 1915, the Italians had won the Falzarego Pass. At times the fighting raged on summits 10,000 feet high, where the thin air exhausted the combatants far quicker than their physical exertions. In the last battle of this engagement the Italians obtained a footing upon a point of great strategical importance three miles beyond the pass on the Sasso d'Istria, close to where the Dolomite road bends southward through the ravine and penetrated the mountains in two tunnels.