Between the armies was a rivulet, bordered on each side with very high banks, and covered around with marshy plants, and with the brushwood and brambles with which uncultivated places are generally overspread; and when, riding around it, he had, with his own eyes, thoroughly reconnoitred a place which was sufficient to afford a covert even for cavalry, he said to Mago his brother: "This will be the place which you must occupy.

Choose out of all the infantry and cavalry a hundred men of each, with whom come to me at the first watch.

Now is the time to refresh their bodies." The council was thus dismissed, and in a little time Mago came forward with his chosen men.
"I see," said Hannibal, "the strength of the men; but that you may be strong not only in resolution, but also in number, pick out each from the troops and companies nine men like yourselves: Mago will show you the place where you are to lie in ambush.

You will have an enemy who is blind to these arts of war." A thousand horse and a thousand foot, under the command of Mago, having been thus sent off, Hannibal orders the Numidian cavalry to ride up, after crossing the river Trebia by break of day, to the gates of the enemy, and to draw them out to a battle by discharging their javelins at the guards; and then, when the fight was commenced, by retiring slowly to decoy them across the river.

These instructions were given to the Numidians: to the other leaders of the infantry and cavalry it was commanded that they should order all their men to dine; and then, under arms and with their horses equipped, to await the signal.