And at first, not knowing whither the Carthaginian was going, they had imagined that their own rocks and forts, and the plunder of their cattle and people, were his objects; but afterwards, the report of the Punic war with which Italy was being desolated for now ten years, had convinced them that the Alps were only a passage, and that two very powerful nations, separated from each other by a vast tract of sea and land, were contending for empire and power.

These were the causes which opened the Alps to Hasdrubal.
But the advantage which he gained by the celerity of his march he lost by his delay at Placentia, while he carried on a fruitless siege, rather than an assault.

He had supposed that it would be easy to take by storm a town situated on a plain; and the celebrity of the colony induced him to believe that by destroying it he should strike great terror into the rest.

This siege not only impeded his own progress, but had the effect of restraining Hannibal, who was just on the point of quitting his winter quarters, after hearing of his passage, which was so much quicker than he expected; for he not only revolved in his mind how tedious was the siege of towns, but also how ineffectual was his attempt upon that same colony, when returning victorious from the Trebia.
40.

The consuls, on departing from the city in different directions, had drawn the attention of the public, as it were, to two wars at once, while they called to mind the disasters which Hannibal's first coming had brought upon Italy, and at the same time, tortured with anxiety, asked themselves what deities would be so propitious to the city and empire as that the commonwealth should be victorious in both quarters at once.