Hannibal, disappointed in his expectations that Capua would be friendly to him, and not being prepared to lay siege to the town, had withdrawn towards the Adriatic.
Fabius intercepted him near Casilinum, in Campania, on the left bank of the Volturnus.

The heights that commanded the right bank of the river were occupied by his main army; and the road itself, which led across the river, was guarded by a strong division of men.
Hannibal, however, ordered his light-armed troops to ascend the heights over the road during the night, driving before them oxen with burning fagots tied to their horns, giving the appearance of an army marching by torchlight.

The plan was successful.

The Romans abandoned the road and marched for the heights, along which they supposed the enemy were going.
Hannibal, with a clear road before him, continued his march with the bulk of his army.

The next morning he recalled his light-armed troops, which had been sent on to the hills with the oxen.