The vast Roman horde made camp about 5 miles away from Hannibal's army. They were supremely confident. The largest army Rome had ever put in the field, they outnumbered Hannibal by a wide margin.
Against his 50,000 men they fielded over 80,000 men. Despite the fact that Hannibal's army was extremely experienced, having served under him for years in Spain and having beaten Roman armies twice sent to stop him, the Roman army, largely composed of raw recruits felt confident because of their overwhelming size.
They expected to win.
On a hot, dry day in 216 BCE the armies drew up on a flat plain and faced one another.
The Legions deployed in a very unusual formation for them. Rather than arrayed rather loosely, which typically gave the Legion a great deal of maneuverability and flexibility, they were arrayed in a tight column formation. Their goal was to punch through the center of Hannibal's line and slaughter his men as they lost unit cohesion, broke and ran.
For his part Hannibal's formation seemed almost pedestrian. He had his skirmshers, the slingers out front, heavy infantry in the middle (though not his best infantry) on the wings he had his best men, his Libyan heavy infantry and on the flanks his cavalry.
Hannibal then took personal command of the infantry in the center and led them toward the Romans, while his other forces lagged behind. This made his line bow outward and appeared to the Romans as a sign of weakness and a lack of cohesion.
It should here be noted that modern historians' claims that this formation of Hannibal's was accidental is not born out by the contemporary accounts. All the Roman historians writing within the time of the battle were quite clear that this was an intentional formation.
Since the point of engagement was so narrow, the Roman Legions packed in even closer to engage the infantry led by Hannibal. They wanted to take part in the victory.
Under intense pressure, the Spanish and Gallic infantry led personally by Hannibal was forced to yield. But it did not break and lose cohesion. Instead it was slowly diven back and the bow of Hannibal's initial assault slowly became inverted from convex to concave. Hannibal's center was now behind his flanking forces.
The Libyans, Hannibal's best infantry waited patiently on the wings. The Roman cavalry fought Hannibal's cavalry more or less equally.
Finally the infantry in the center broke, drawing the Romans in even further as they pursued the enemy for the anticipated slaughter. It is at this exact moment that the Libyan heavy infantry turned and charged both Roman flanks.
At this point Hannibal's cavalry broke through, putting the Roman and Italian cavalry to flight. Just as the beleaguered Romans realized they were being assaulted on both flanks, Hannibal's heaviest cavalry attacked them from the rear.
In one of the greatest maneuvers in military history Hannibal had in effect ambushed his opponent on an open plain. In fact, when the cavalry attacked the Roman rear he had achieved a complete encirclement of a force that outnumbered his own.
The battlefield became a slaughterhouse of Roman dead.
Of the massive force fielded by the Romans 3,000 infantry and 370 cavalry were all that survived. For his part Hannibal lost only 6,000 men, almost all of them from the hard-pressed center he had personally commanded.
to be continued...