The natural negligence of the general was now increased by the hope that their attachment to the Carthaginians was shaken when they had heard that Hannibal, after the loss of Salapia, had retired from that neighbourhood into Bruttium.
Intelligence of all these circumstances being conveyed to Hannibal by secret messengers from Herdonea, at once excited an anxious desire to retain possession of a city in alliance with him, and inspired a hope of attacking the enemy when unprepared.

With a lightly equipped force he hastened to Herdonea by forced marches, so as almost to anticipate the report of his approach and in order to strike greater terror into the enemy, came up with his troops in battle-array.

The Roman, equal to him in courage, but inferior in strength, hastily drawing out his troops, engaged him.

The fifth legion and the left wing of the allied infantry commenced the battle with spirit.

But Hannibal ordered his cavalry, on a signal given, to ride round as soon as the foot forces had their eyes and thoughts occupied with the contest before them, and one half of them to attack the camp of the enemy, the other half to fall upon their rear, while busily engaged in fighting.