Wurmser, when he fixed his headquarters at Trent, mustered in all 80,000; while Buonaparte had but 30,000, to hold a wide country, in which abhorrence of the French cause was now prevalent, to keep up the blockade of Mantua, and to oppose this fearful odds of numbers in the field. He was now, moreover, to act on the defensive, while his adversary assumed the more inspiriting character of invader. He awaited the result with calmness.
Wurmser might have learned from the successes of Buonaparte the advantages of compact movement; yet he was unwise enough to divide his great force into three separate columns, and to place one of these upon a line of march which entirely separated it from the support of the others. He himself, with his centre, came down on the left bank of the Lago di Guarda, with Mantua before him as his mark: his left wing, under Melas, was to descend the Adige, and drive the French from Verona; while the right wing, under Quasdonowich, were ordered to keep down the valley of the Chiese, in the direction of Brescia, and so to cut off the retreat of Buonaparte upon the Milanese;--in other words, to interpose the waters of the Lago di Guarda between themselves and the march of their friends--a blunder not likely to escape the eagle eye of Napoleon.
He immediately determined to march against Quasdonowich, and fight him where he could not be supported by the other two columns. This could not be done without abandoning for the time the blockade of Mantua; but it was not for Buonaparte to hesitate about purchasing a great ultimate advantage by a present sacrifice, however disagreeable. The guns were buried in the trenches during the night of the 31st July, and the French quitted the place with a precipitation which the advancing Austrians considered as the result of terror.
Napoleon meanwhile rushed against Quasdonowich, who had already come near the bottom of the Lake of Guarda. At Salo, close by the lake, and, further from it, at Lonato, two divisions of the Austrian column were attacked and overwhelmed. Augereau and Massena, leaving merely rear-guards at Borghetto and Peschiera, now marched also upon Brescia. The whole force of Quasdonowich must inevitably have been ruined by these combinations, had he stood his ground; but by this time the celerity of Napoleon had overawed him, and he was already in full retreat upon his old quarters in the Tyrol. Augereau and Massena, therefore, countermarched their columns, and returned towards the Mincio. They found that Wurmser had forced their rear-guards from their posts: that of Massena, under Pigeon, had retired in good order to Lonato; that of Augereau, under Vallette, had retreated in confusion, abandoning Castiglione to the Austrians.