Beaulieu had retired beyond the Po and the Ticino, expecting that the attack on the Milanese would be delivered across the latter stream by the ordinary route, which crossed it at Pavia.

Near that city the Austrians occupied a strong position with 26,000 men, while other detachments patrolled the banks of the Ticino further north, and those of the Po towards Valenza, only 5,000 men being sent towards Piacenza.

Bonaparte, however, was not minded to take the ordinary route.

He determined to march, not as yet on the north of the River Po, where snow-swollen streams coursed down from the Alps, but rather on the south side, where the Apennines throw off fewer streams and also of smaller volume.

From the fortress of Tortona he could make a rush at Piacenza, cross the Po there, and thus gain the Milanese almost without a blow.