Talk of this sort had procured for him his second consulship, and hopes of this sort had now brought to his camp so great a multitude of unarmed followers eager for spoil, that their number, according to the assurance of sober historians, exceeded that of the legionaries.
Hannibal based his plan in part on this circumstance.

So far from attacking him, he marched past him, and caused the country all around to be pillaged by the Celts who thoroughly understood plundering, and by his numerous cavalry.

The complaints and indignation of the multitude which had to submit to be plundered under the eyes of the hero who had promised to enrich them, and the protestation of the enemy that they did not believe him possessed of either the power or the resolution to undertake anything before the arrival of his colleague, could not but induce such a man to display his genius for strategy, and to give a sharp lesson to his inconsiderate and haughty foe.
Battle on the Trasimene Lake No plan was ever more successful.

In haste, the consul followed the line of march of the enemy, who passed by Arezzo and moved slowly through the rich valley of the Chiana towards Perugia.

He overtook him in the district of Cortona, where Hannibal, accurately informed of his antagonist's march, had had full time to select his field of battle--a narrow defile between two steep mountain walls, closed at its outlet by a high hill, and at its entrance by the Trasimene lake.
With the flower of his infantry he barred the outlet; the light troops and the cavalry placed themselves in concealment on either side.