Minucius, elated with his elevation, proposed to Fabius either that they should command the whole army on alternate days, or each should permanently command one-half.  Fabius chose the latter alternative, for he felt certain that the impetuosity of his colleague would sooner or later get him into trouble with such an adversary as Hannibal, and that it was better to risk the destruction of half the army than of the whole.

Minucius withdrew the troops allotted to him, and encamped in the plains at a distance of a mile and a half from Fabius.  Hannibal resolved at once to take advantage of the change, and to tempt the Romans to attack him by occupying a hill which lay about halfway between the camp of Minucius and Geronium.

The plain which surrounded the hill was level and destitute of wood, but Hannibal on a careful examination found that there were several hollows in which troops could be concealed, and in these during the night he posted five thousand infantry and five hundred cavalry.  The position occupied by them was such that they would be able to take the Romans in flank and rear should they advance against the hill.  Having made these dispositions he sent forward a body of light troops in the morning to occupy the hill.  Minucius immediately despatched his light troops, supported by cavalry, to drive them from it.  Hannibal reinforced his Carthaginians by small bodies of troops, and the fight was obstinately maintained until Minucius, whose blood was now up, marched towards the hill with his legions in order of battle.

Hannibal on his side advanced with the remains of his troops, and the battle became fierce and general, until Hannibal gave the signal to his troops in ambush, who rushed out and charged the Romans in rear and flank.  Their destruction would have been as complete and terrible as that which had befallen the army of Sempronius at the Trebia, had not Fabius moved forward with his troops to save the broken legions of Minucius.

Fabius now offered battle, but Hannibal, well content with the heavy blow which he had struck, and the great loss which he had inflicted upon the command of Minucius, fell back to his camp.  Minucius acknowledged that Fabius had saved his army from total destruction, and at once resigned his command into his hands, and reverted to his former position under him.  Both armies then went into winter quarters.

Malchus had not been present at the fighting near Geronium.  Two days after Hannibal broke through the Roman positions round the plains of Campania he intrusted Malchus with an important commission.  Commanding the bodyguard of the general, and being closely related to him, Malchus was greatly in Hannibal’s confidence, and was indeed on the same footing with Mago, Hannibal’s brother, and two or three other of his most trusted generals.  Gathered in the general’s tent on the previous evening, these had agreed with their leader that final success could not be looked for in their enterprise unless reinforcements were received from Carthage.