It was by this stream, famed in war as in song, that the Imperialists now halted their shattered forces, awaiting reinforcements from Tyrol.  These would pass down the valley of the Adige, and in the last part of their march would cross the lands of the Venetian Republic.  For this action there was a long-established right of way, which did not involve a breach of the neutrality of Venice.  But, as some of the Austrian troops had straggled on to the Venetian territory south of Brescia, the French commander had no hesitation in openly violating Venetian neutrality by the occupation of that town (May 26th).  Augereau’s division was also ordered to push on towards the west shore of Lake Garda, and there collect boats as if a crossing were intended.  Seeing this, the Austrians seized the small Venetian fortress of Peschiera, which commands the exit of the Mincio from the lake, and Venetian neutrality was thenceforth wholly disregarded.

By adroit moves on the borders of the lake, Bonaparte now sought to make Beaulieu nervous about his communications with Tyrol through the river valley of the Adige; he completely succeeded:  seeking to guard the important positions on that river between Rivoli and Roveredo, Beaulieu so weakened his forces on the Mincio, that at Borghetto and Valeggio he had only two battalions and ten squadrons of horse, or about two thousand men.  Lannes’ grenadiers, therefore, had little difficulty in forcing a passage on May 30th, whereupon Beaulieu withdrew to the upper Adige, highly satisfied with himself for having victualled the fortress of Mantua so that it could withstand a long siege.  This was, practically, his sole achievement in the campaign.  Outnumbered, outgeneralled, bankrupt in health as in reputation, he soon resigned his command, but not before he had given signs of “downright dotage."[54] He had, however, achieved immortality:  his incapacity threw into brilliant relief the genius of his young antagonist, and therefore appreciably affected the fortunes of Italy and of Europe.

Bonaparte now despatched Massena’s division northwards, to coop up the Austrians in the narrow valley of the upper Adige, while other regiments began to close in on Mantua.  The peculiarities of the ground favoured its investment.  The semicircular lagoon which guards Mantua on the north, and the marshes on the south side, render an assault very difficult; but they also limit the range of ground over which sorties can be made, thereby lightening the work of the besiegers; and during part of the blockade Napoleon left fewer than five thousand men for this purpose.  It was clear, however, that the reduction of Mantua would be a tedious undertaking, such as Bonaparte’s daring and enterprising genius could ill brook, and that his cherished design of marching northwards to effect a junction with Moreau on the Danube was impossible.  Having only 40,400 men with him at midsummer, he had barely enough to hold the line of the Adige, to blockade Mantua, and to keep open his communications with France.