Quote Originally Posted by EvilNed
No, I'm quite sure Hannibal DID order his Iberian mercenaries to feign retreat. He did this so that the romans would advance, and make the whole ordeal so much easier for his troops to envelop the romans. This was, of course, succesfull, and he didn't have to loose as many troops as he might have done otherwise.

EDIT:

http://www.roman-empire.net/army/cannae.html

"The crescent of Celtic and Spanish swordsmen buckled and retreated. To the Romans this appeared to be due to their powerful drive into the opponents lines. In fact the troops had been told to retreat."
You have misinterpreted what the site says. It does not say feigned retreat. Read Polybius. This is not a "feigned" retreat. It is a real retreat of troops falling back/buckling as things get too hot. Hannibal's center was vastly outnumbered and on open ground. The troops fought, and gave ground as planned. Hannibal used the classic strategy (tactic in this case) of trading space for time. No, the center was not intended to hold its ground, Hannibal knew it would buckle, just as it had at Trebbia. This is not a feigned retreat, it is a fighting withdrawal. "Giving ground" is a clear indication of the nature of the central action.


Polybius 3.115 from Perseus:
For a short time the Iberian and Celtic lines stood their ground and fought gallantly; but; presently overpowered by the weight of the heavy-armed lines, they gave way and retired to the rear, thus breaking up the crescent. The Roman maniples followed with spirit, and easily cut their way through the enemy's line; since the Celts had been drawn up in a thin line, while the Romans had closed up from the wings towards the centre and the point of danger. For the two wings did not come into action at the same time as the centre: but the centre was first engaged, because the Gauls, having been stationed on the arc of the crescent, had come into contact with the enemy long before the wings, the convex of the crescent being towards the enemy.
The Romans, however, going in pursuit of these troops, and hastily closing in towards the centre and the part of the enemy which was giving ground, advanced so far, that the Libyan heavy-armed troops on either wing got on their flanks. Those on the right, facing to the left, charged from the right upon the Roman flank; while those who were on the left wing faced to the right, and, dressing by the left, charged their right flank,1 the exigency of the moment suggesting to them what they ought to do. Thus it came about, as Hannibal had planned, that the Romans were caught between two hostile lines of Libyans--thanks to their impetuous pursuit of the Celts.