The place which Hannibal chose for his battle was close to lake Thrasymene, a reedy basin in the mountains not far from the city of Cortona. At this spot a narrow valley ran down to the lake, with lines of hills on both sides, and a very steep mountain at the opposite end of the lake. At the lake end the hills came so close together that there was only a small track through which a few men could pass at a time.

Making sure that his enemy was following in his footsteps, Hannibal placed his steady heavy armed Spaniards and Libyans on the hill at the end of the valley opposite the lake, in full view of anyone who might approach them. His Balearic slingers and archers, and light-armed troops, were hidden behind the rocks of the hills on the right, and the Gauls and cavalry were posted in gorges on the left, close to the entrance of the defile, but concealed by folds in the ground. Next day Flaminius arrived at the lake, and, as Hannibal intended, perceived the camp on the hill opposite. It was too late to attack that night, but the next morning, in a thick mist, the consul gave orders for the advance through the pass. Grimly smiling at the success of his scheme, Hannibal waited till the Romans were quite close to him, and then gave the signal for the assault from all three sides at once.

Never in the whole of history was a rout more sudden and more complete. Flaminius' army was enclosed in a basin, and in the thick fog could get no idea from which direction the enemy was coming. The soldiers seemed to have sprung right out of the earth, and to be attacking on every quarter. All that the Romans could do was to fight, and fight they did with desperation. But there was no one to lead them, for their generals, like themselves, were bewildered, and Flaminius speedily met with the fate his folly deserved. Fifteen thousand Romans fell that day in the fierce battle, during which even an earthquake passed unheeded. Multitudes were pushed back into the lake and were dragged down to the bottom by the weight of their armour. Some fled to the hills and surrendered on the promise of their lives being spared, and a few thousands found their way back to Rome.

The victory being won, Hannibal charged the soldiers to seek for the body of Flaminius, so that he might give it honourable burial, by which nations in ancient times set special store. But, search as they might, they could not find it, nor was it ever known what became of him. Very differently did the Roman general Nero behave eleven years later on the banks of the Metaurus, when Hannibal's brother Hasdrubal, seeing that the day was lost, rode straight into the ranks of the enemy. When he fell, Nero, with savagery worthy of his namesake the emperor, cut off the head of the Carthaginian and threw it into Hannibal's camp.

Fifteen thousand Romans fell that day.

There was silence in Rome when bands of wounded and weary soldiers came flying to the gates, bearing the news of this fresh disaster. Fifteen thousand men slain, fifteen thousand men taken prisoners! Hardly a family in Rome that was not stricken, and who could tell when the banners of the Carthaginians might not be seen on the crests of the hills? But as the troubles of life show the stuff of which men are made, Romans were never so great as when their cause seemed hopeless. The city was at once put in a state of defence, every boy and old man that could bear arms was sent to the walls, the bridges over the Tiber were destroyed, and the senate, putting aside the consuls, elected a dictator, who for six months had absolute power over the whole state.

The man who in this hour of sorest need was chosen to save the city was Quintus Fabius, whose policy of 'waiting' has become a proverb even to this day. He was already old, and was never a brilliant general, but, like most Romans, possessed great common-sense.

Alone among the senate he saw that there was no hope of conquering Hannibal in a pitched battle. Rome had not then—and, except for Cæsar, never has had—a single general with a genius equal to his; but there was one way, and one only, by which he might be vanquished, and that was to leave him where he was, in the midst of a hostile country, till his troops grew weary of expecting a battle which never was fought, and his Gallic allies became tired of inaction and deserted him.