Between Lake Garda and the Adige large Austrian forces were massed on May 22, 1916, in the Riva zone. There was also considerable aerial activity on that day on Monte Baldo (the mountain ridge to the east of the lake). From the Adige to the Astico there were only reconnoiterings. Between the Astico and the Brenta Rivers in the Sugana Valley, the Italians were again forced to fall back gradually on their main lines after repulsing heavy attacks throughout the day. The retreat, however, was orderly and spontaneous. Besides accomplishing their advance in the Val Sugana, the Austrians continued the reduction of the forts protecting Arsiero, well across the Italian frontier on the way toward Vicenza. Arsiero is the terminus of a railway leading down into the Vicenza plain and the city of Vicenza. Through the capture of the Spitz Tonezza and Monte Melignone the Austrians now held the entire line across the frontier as far as Forni on the Astico. They also pushed their advance toward the ridge north of the Val dei Laghi, and toward Monte Tormino and Monte Cremone, all three outlying defenses of Arsiero. Meanwhile the right wing of the Austrian army, after storming Col Santo, had moved toward Monte Pasubio, and the left wing had stormed the Sasso Alto, commanding the Armentara Ridge, enabling the Austrians to advance into the Sugana Valley and to take Roncegno. In order to appreciate the difficulties connected with all of this fighting, it must be remembered that the fighting is going on in the mountains, on ground varying in altitude as much as 5,000 feet per mile. The mountains were still partly covered with snow and the transportation of supplies, therefore, was exceedingly difficult. As the month of May drew to its end, the Austrian advance spread steadily. By May 23, 1916, the Austrians had occupied north of the Sugana Valley the ridge from Salubio to Borgo. On the frontier ridge south of the valley the Italians were driven from Pompeii Mountain. Further south the Italians successfully defended the heights east of the Val d'Assa and the fortified district Asiago and Arsiero. The armored work of Campolono, however, fell into Austro-Hungarian hands. The Austro-Hungarian troops approached more closely the Val d'Assa and Posina Valley. Orderly as the Italian retreat was, it was nevertheless a hasty one. For the official Italian report for May 23, 1916, admits that artillery "that could not be removed" was destroyed. Both the violence and unexpectedness of the Austrian attacks are testified to by articles published at this time in Italian newspapers. A writer in the "Giornale d'Italia" of Rome says that "the Austrian offensive came as a surprise to the Italian command and the taking of Monte Maggio and other important positions was possible, because the Italians were not looking for so heavy an attack."