Mantua was meanwhile invested, and thither, after his brief incursion into Central Italy, Bonaparte returned. Towards the end of July an Austrian relieving army, nearly double the strength of Bonaparte's, descended from the Tyrol. It was divided into three corps: one, under Quosdanovich, advanced by the road on the west of Lake Garda; the others, under Wurmser, the commander-in-chief, by the roads between the lake and the river Adige. The peril of the French was extreme; their outlying divisions were defeated and driven in; Bonaparte could only hope to save himself by collecting all his forces at the foot of the lake, and striking at one or other of the Austrian armies before they effected their junction on the Mincio. He instantly broke up the siege of Mantua, and withdrew from every position east of the river. On the 30th of July, Quosdanovich was attacked and checked at Lonato, on the west of the Lake of Garda. Wurmser, unaware of his colleague's repulse, entered Mantua in triumph, and then set out, expecting to envelop Bonaparte between two fires. But the French were ready for his approach. Wurmser was stopped and defeated at Castiglione, while the western Austrian divisions were still held in check at Lonato. The junction of the Austrian armies had become impossible. In five days the skill of Bonaparte and the unsparing exertions of his soldiery had more than retrieved all that appeared to have been lost. [50] The Austrians retired into the Tyrol, beaten and dispirited, and leaving 15,000 prisoners in the hands of the enemy. Bonaparte now prepared to force his way into Germany by the Adige, in fulfilment of the original plan of the campaign. In the first days of September he again routed the Austrians, and gained possession of Roveredo and Trent. Wurmser hereupon attempted to shut the French up in the mountains by a movement southwards; but, while he operated with insufficient forces between the Brenta and the Adige, he was cut off from Germany, and only escaped capture by throwing himself into Mantua with the shattered remnant of his army. The road into Germany through the Tyrol now lay open; but in the midst of his victories Bonaparte learnt that the northern armies of Moreau and Jourdan, with which he had intended to co-operate in an attack upon Vienna, were in full retreat. [Invasion of Germany by Moreau and Jourdan, June-Oct., 1796.] [The Archduke Charles overpowers Jourdan.]