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.