While regular siege operations were being carried on against Tolmino and Gorizia, the Italians were putting forth great efforts to secure possession of the Carso Plateau, which dominates the rail and carriage road between Monfalcone and Trieste, as well as the Isonzo Valley up to Gorizia. The plateau had to be completely occupied before any advance could be made along the coast road into Istria and before Gorizia could be attacked from the south. Two months after the declaration of war the Italians, who by that time were in possession of the bridgehead at Sagrada, stormed with great gallantry several lines of trenches on the summit of the western face of the plateau, and captured two thousand prisoners with a large quantity of war material. They followed up this success by an infantry attack, supported by a large number of heavy and field guns. Farther north another army operated against Tarvis along two routes, one of which goes over the Pontafel Pass and is traversed by the railroad running between Vienna and Venice, while the other is a coach road leading from Plezzo over the Predil Pass to the Save Valley. The progress of the Italian columns was checked at Malborgeth, where the Austrians had constructed a chain of permanent forts, while along the coach road an equally strong group of forts covering the Predil Pass blocked the way. A further offensive was directed across the Carnic Alps by way of the Kreuzberg Pass down the Seoten Valley to Innichen and Toblach on the Pusterthal railway. Formidable works had been constructed at Seoten and Lambeo, covering the approaches to the railroad, and on these the Italians opened a furious bombardment for the purpose of clearing a way into the Drave Valley. The object aimed at here was very clear to the Austrians, for when the railroad was reached communication along the Pusterthal between the Adige and Isonzo would be cut, and the Austrian position on the Trentino turned. This was the position in August, 1915, when the Italians were exerting pressure on the Austrians for the further purpose of diverting troops from the Russian frontier, where was being carried on the greatest offensive known to history.