Furthermore, northern Italy offered Melas many advantages for a defensive campaign. If hard pressed by Masséna, he could fall back to the Mincio, a strong position, flanked on the right by Lake Garda and on the left by the fortress of Mantua. If defeated in this position, he could retire into the Tyrol, where he would directly cover his communications with the valley of the Danube. In the mountains and defiles of the Tyrol, he could, if hard pressed, fall back to another strong position, fight again, and thus prolong the conflict. Moreover, Masséna could not advance eastward through Friuli towards Austria so long as fifty thousand Austrians remained in the Tyrol; for they could then descend upon the flank and rear of the Army of Italy, and could sever the French communications without exposing their own to Masséna's attacks. Of still greater importance, however, is the fact that, had Masséna driven Melas through the Tyrol, or across the Carnic Alps, his success would have had little or no effect upon the operations of the one hundred and ninety thousand Austrians in the valley of the Danube. And why? Because the route between France and Austria through northern Italy was longer than that through the valley of the Danube. Because the mountains of Austria on the side towards Italy offered strong defensive positions near the Austrian capital. Because the vital point of the theatre of operations was in western Germany, and not in northern Italy. The proof of this will be apparent when we examine the Italian campaign of 1796-97. Though Bonaparte fought his way through northern Italy, and crossed the Alps into Austria, this movement had scarcely any effect upon the operations of the Austrian army that was facing the two French armies, under Moreau and Hoche, on the Rhine in the vicinity of the Black Forest.