TRENTINO, a mountainous area of North Italy, extending E. and W. of the middle course of the Adige. Before the World War it was part of the Austrian province of Tirol. The Trentino frontier, which had been delimited after the war of 1866, was strategically most unfavourable to Italy, as it left the mountain ranges wholly in Austrian hands and formed a wedge whence a dozen military roads branched outwards threatening the richest and most fertile parts of Italy. It also left 400,000 Italians un der Austrian rule. During the war the Trentino was the scene of heavy fighting, which extended from the Stelvio pass to the Ampezzo valley and spread over into the Asiago plateau within the borders of Italy. Early in the war the Italian troops occupied a number of positions beyond the frontier, especially east of the Adige, whence their line extended from north of Mori, along the Terragnolo valley, Costa d'Agra, across the Astico, Cima Man driolo, across the river Brenta in the Val Sugana to the Cima d'Asta; farther east all the Ampezzo valley was occupied to the Tofana and Cristallo groups. There were many engagements in the autumn and winter of 1915, especially north of the Cadore and at the head of the Cordevole valley round the Col di Lana, the attacks on which caused serious losses to the Italians, until in April 1916 the summit was blown up by an Italian mine and the hill remained in Italian hands. The fighting on the Stelvio, the Adamello, the Ampezzo group and the peaks round San Martino di Castrozza was at a very high altitude, and the troops had to perform what even in ordinary times would be regarded as notable mountaineering exploits amid ice, snow and extremely difficult rocky terrain, exposed to intense cold, severe storms and heavy enemy fire, the Austrians usually holding the most favour able positions. Roads had to be built up the most precipitous mountains and heavy guns dragged up to a height of 2,000 to 3,000 feet. The Italians managed to capture many of these positions,
although at the cost of heavy losses ; but in May 1916 the Aus trians, after an intense artillery preparation with masses of heavy guns, launched a formidable attack on the Terragnolo—Val Sugana —Folgaria—Asiago area and drove the Italians back for a con siderable distance. The object was to debouch into the Vicenza plain and cut the communications with the Isonzo army. There was desperate fighting along the whole line, but the key positions of Coni Zugna, Passo Buole and the Pasubio to the west and the peaks on the outer edge of the Asiago plateau on the east held firm. By June 16 the momentum of the Austrians had exhausted itself, and an Italian counter-attack recovered most of the lost ground. After the Austrian break-through at Caporetto in Oct. 1917, an attempt was made to effect a breach also in the Asiago plateau. The Ampezzo and Cadore areas had to be evacuated by the Italians, and in the heavy fighting through Nov. and Dec. some of the positions on the plateau were again lost, but the outer edge was held, and the Austrians failed to descend into the plain. In the battle of June 1918, when the west sector of the Asiago area was held by British troops, another attack was de livered there, and although the Austrians at first broke through at several points they were driven back to their original line. When the final battle of the war began (Oct. 23, 1918) the Italians, together with British and French forces, carried out a demonstra tive action to prevent the enemy from shifting reserves to the Grappa and Piave areas where the main attacks were being de livered. It was from the Asiago plateau that the victorious troops on Nov. I poured into the Val Sugana, while the I. Army advanced up the Adige valley and the two forces converged on Trento, which was reached on Nov. 3.