+21.+ Mago thought that it would be an excellent moment to attack the Romans while actually engaged in making their camp; he therefore rode up to the entrenchment with the greater part of his own cavalry and Massanissa with the Numidians, persuaded that he should catch Scipio off his guard. Scipio had however all along foreseen this, and had placed some cavalry equal in number to those of the Carthaginians under cover of some hills. Upon these making an unexpected charge, many of the enemy’s horsemen at once took to flight at the startling appearance, and began to make off; while the rest closed with their opponents and fought with great gallantry. But the Carthaginians were disconcerted by the agility of some of the Roman horsemen in dismounting, and after a short resistance they retreated with considerable loss. The retreat was at first conducted in good order: but as the Romans pressed them hard, they broke up their squadrons, and fled for safety to their own camp. This affair gave the Romans better spirits for engaging in a pitched battle, and had the contrary effect on the Carthaginians. However, during the next few days they both drew out on the intervening plain; skirmished with their cavalry and light-armed troops; and, after thus trying each other’s mettle, were resolved to bring the matter to the test of a general engagement. [Sidenote: Scipio resolves on a general engagement, and alters his disposition so as to make the battle depend upon the Italians rather than the Spaniards.] +22.+ On this occasion Scipio appears to have employed a twofold stratagem. Hasdrubal had been accustomed to make his demonstrations in force somewhat late in the day, with the Libyans in his centre, and the elephants on either wing; while his own practice had been to make his counter-movements somewhat later still, with the Roman soldiers on his centre opposite the Libyans, and the Iberians on his two wings; but the day on which he resolved upon a general engagement, by reversing this arrangement, he greatly contributed to secure the victory for his own men, and succeeded in putting the enemy at a considerable disadvantage. For directly it was light he sent his aides with orders to the tribunes and men to arm, as soon as they had got their breakfasts, and parade outside the camp. The order was obeyed with alacrity because the men suspected what was going to take place. He then sent the cavalry and light-armed forward, with orders to advance close to the enemy’s camp, and skirmish boldly up to it; while he himself marched out with the infantry, just as the sun was appearing above the horizon; and on reaching the middle of the plain, made his dispositions in the reverse order to his usual arrangement, placing the Iberians in the centre and the Roman legionaries on the two wings.