As soon as the battle was over Hannibal despatched Maharbal with his division of the army in pursuit of the six thousand who had escaped, and, overtaking them next morning at Perugia, Maharbal forced them to surrender.  At the same time he detached a strong force against the four thousand horsemen, whom Servilius had despatched from Rimini to aid his colleague, and the whole of these were surrounded and taken prisoners.  Thus of the Roman army, thirty-six thousand strong, not a single man escaped.

In all history there is no record of so great and successful a surprise.  Hannibal retained as prisoners the Roman citizens and Latins, but released the rest of the captives, telling them that, far from being their enemy, he had invaded Italy for the purpose of liberating its helpless people from the tyranny of the Roman domination.  The loss to the Carthaginians in the battle of Lake Trasimene was only fifteen hundred men.

Hannibal has been blamed for not advancing against Rome after the battle of Lake Trasimene; but he knew that he could not hope to subdue that city so long as she was surrounded by faithful allies.  His army was numerically insufficient to undertake such a siege, and was destitute of the machines for battering the walls.  Rome was still defended by the city legions, besides which every man capable of bearing arms was a soldier.  The bitter hostility of the Latins would have rendered it difficult in the extreme for the army to have obtained provisions while carrying on the siege, while in its rear, waiting for an opportunity to attack, would have lain the army of Servilius, thirty thousand strong, and growing daily more numerous as the friends and allies of Rome flocked to its banners.

Hannibal saw that to undertake such an enterprise at present would be ruin.  His course was clear.  He had to beat the armies which Rome could put into the field; to shake the confidence of the Italian tribes in the power of Rome; to subsist his army upon their territories, and so gradually to detach them from their alliance with Rome.  He hoped that, by the time this work was finished, Carthage would send another great army to his assistance provided with siege materials, and he would then be able to undertake with confidence the great task of striking a vital blow at Rome herself.

“Malchus,” Hannibal said one day, “I wish you to ride north.  The tribes at the foot of the hills promised to aid us, but have so far done nothing.  If they would pour down to the plains now they would occupy the tribes friendly to the Romans, and would prevent them from sending men and stores to them.  They sent me a message a month ago, saying that they were still willing to help us, and I then replied that I had been long waiting to hear that they had risen, and urged them to do so without loss of time.  I have not heard since, and fear that the Roman agents have, by promises of money and privileges, prevailed upon them to keep quiet.  It is a service of danger; for if they have been bought over they may seize you and send you in token of their goodwill as a prisoner to Rome; but I know that will not deter you.”